in the united states district court for the ......upon information and belief, defendant micron...

IN THE UNITED STATES DISTRICT COURT

FOR THE DISTRICT OF MASSACHUSETTS

PRESIDENT AND FELLOWS OF

HARVARD COLLEGE

Plaintiff,

v.

MICRON TECHNOLOGY, INC.

Defendant.

Defendant.

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COMPLAINT

Civil Action No. ___________

JURY TRIAL DEMANDED

COMPLAINT

Plaintiff, President and Fellows of Harvard College (“Harvard”), by and through its

counsel, Pepper Hamilton LLP, for its Complaint against Defendant Micron Technology, Inc.

(“Micron”), alleges as follows:

THE PARTIES

1. Plaintiff Harvard is an educational institution and charitable corporation

organized under the laws of the Commonwealth of Massachusetts with its principal place of

business at Massachusetts Hall, Cambridge, MA 02138.

2. Upon information and belief, Defendant Micron Technology, Inc. is a Delaware

corporation with its principal place of business at 8000 S. Federal Way, Boise, ID 83707.

JURISDICTION AND VENUE

3. This is an action for patent infringement arising under the Patent Laws of the

United States, 35 U.S.C. § 1 et. seq. This Court has jurisdiction over the subject matter of this

action pursuant to 28 U.S.C. §§ 1331 and 1338(a).

Case 1:16-cv-11249 Document 1 Filed 06/24/16 of 23

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4. This Court has personal jurisdiction over Micron at least based upon Micron’s

contacts with the forum and the nature of the infringing activity alleged herein. Upon

information and belief, Micron regularly does or solicits business, engages in other persistent

courses of conduct, and/or derives substantial revenue from products and/or services provided to

individuals in the Commonwealth of Massachusetts. Upon information and belief Micron has

committed acts of patent infringement within the Commonwealth of Massachusetts by, inter alia,

selling, offering for sale, importing products manufactured by processes, and/or using materials

that infringe one or more claims of the patents asserted herein. Further, the exercise of personal

jurisdiction comports with Due Process under the United States Constitution.

5. Venue is proper in this district pursuant to 28 U.S.C. §§ 1391(b) and 1400.

BACKGROUND

6. Established in 1636, Harvard is the nation’s oldest institution of higher learning

and is recognized as one of the world’s leading academic institutions. The range of research

activities at Harvard is broad and deep. Harvard scholars conduct research in almost every field

of knowledge and constantly seek to expand human knowledge through analysis, innovation, and

insight. Research at Harvard is supported by more than $800 million of sponsored research

funds each year. Researchers include faculty members, visiting scholars, post-doctoral fellows,

and graduate and undergraduate students. These researchers collaborate with colleagues across

Harvard, at Harvard-affiliated institutions, at other research institutions, and with private

corporations throughout the world.

7. Harvard has a long history of benefiting the public through its research programs.

Harvard recognizes that the public benefits from new products and processes resulting from

discoveries and inventions made by individuals connected with Harvard in the course of their

scholarly and research activities. Harvard protects and manages the intellectual property that


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results from the efforts of its researchers, to the benefit of, among others, the researchers,

Harvard, and the public.

8. Professor Roy G. Gordon has worked for and performed research in Harvard’s

Department of Chemistry for over 50 years. Professor Gordon has served as Chairman of the

Department of Chemistry and is the Thomas D. Cabot Professor of Chemistry. The Department

of Chemistry at Harvard, through its faculty, students, postdoctoral fellows, and other research

scholars, work in first-class facilities on individual investigator-led research projects and in

collaboration with others in a broad spectrum of chemistry topics.

9. Professor Gordon’s research has spanned a wide range of subjects including

applied mathematics, quantum mechanics, spectroscopy, intermolecular forces, solid state, and

materials science. His theoretical work has led to a better understanding of bonding in molecules

and solids, and to predictions of new solid phases and phase transitions. Currently the chemical

kinetics of crystal growth from vapor systems is being studied both theoretically and

experimentally in his laboratory. His discoveries of new materials and vapor deposition

processes are widely used commercially for making thin films in solar cells, energy-conserving

window coatings, display devices, and semiconductor electronics.

10. Professor Gordon, along with Drs. Jill Becker, Dennis Hausmann, and Seigi Suh

are named inventors on U.S. Patent Nos. 6,969,539 and 8,334,016 (collectively, “the Asserted

Patents”). Harvard is the assignee of each of the Asserted Patents and owns all right, title, and

interest in the Asserted Patents.

11. The inventions claimed by the Asserted Patents include novel processes and

materials for deposition of thin films that contain metal oxides, silicates, metal phosphates, or


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silicon dioxide. Such films are essential to key components of numerous products such as

computers and cell phones.

12. Some of the claimed inventions include atomic layer deposition (“ALD”). ALD

is a process by which thin films for microelectronics are produced. ALD requires a number of

process steps, one of which is the use of a chemical precursor with appropriate reactive

properties, e.g., to form a dielectric layer. However, problems can occur with the use of ALD for

the fabrication of small sized semiconductors. For example, problems can occur in forming

dielectric materials in deep trench structures, such as those found in dynamic random access

memory (“DRAM”) devices. Not only must the capacitance values remain at a certain level

despite the small size, but the precursor must also be delivered deep into the trenches without

causing a premature reaction that precludes uniform coverage within the entire deep-trench

structure.

13. The ALD processes and materials claimed by the Asserted Patents solve some of

the problems associated with the production of semiconductors at smaller sizes. The inventions

claimed by the Asserted Patents provide a viable solution for the semiconductor industry,

including a solution to forming dielectric materials in deep-trench structures, such as those found

in DRAM devices.

14. Micron advertises that it is a leader in advanced semiconductor systems with a

broad portfolio of high-performance memory technologies, including DRAM, as well as other

types of memory, such as NAND Flash. Upon information and belief, Micron markets its

products through its internal sales force, independent sales representatives, and distributors to

original equipment manufacturers and retailers around the world, including throughout the

United States and within the Commonwealth of Massachusetts. Micron obtains the products it


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sells from wholly-owned manufacturing facilities, including manufacturing facilities in the

United States. Micron continually offers new generations of products with improved

performance characteristics, including higher data transfer rates, reduced package sizes, lower

power consumption, improved read/write reliability, and increased memory density. In 2015, the

majority of Micron’s DRAM production was manufactured with 25nm line-width process

technologies. Micron expects that by the second half of 2016, the majority of its DRAM

production will be manufactured on its 20nm line-width process technology.1

15. Upon information and belief, Micron’s manufacturing facilities in the United

States manufacture certain products in an infringing manner, using ALD processes and materials

claimed by the Asserted Patents. For example, upon information and belief, Micron’s

manufacturing facilities in the United States manufacture DRAM devices using the ALD

processes and materials claimed by the Asserted Patents.

16. Upon information and belief, Micron’s products that are manufactured using the

ALD processes and materials claimed by the Asserted Patents are sold individually, as well as

incorporated into computing, consumer, enterprise, networking, mobile, and automotive

products, throughout the United States, including within the Commonwealth of Massachusetts.

For example, Micron’s DDR4 DRAM is sold individually, and incorporated in other products,

throughout the United States, including within the Commonwealth of Massachusetts.

17. Micron operates a public website, micron.com, which is accessible in the

Commonwealth of Massachusetts. Through micron.com, Micron advertises its products, such as

its DRAM memory. Micron’s website provides, among other information, technical and

1 2015 Annual Report on Form 10-K of Micron Technology, Inc., available at

http://investors.micron.com/sec.cfm?view=all.


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purchasing information regarding its products. Micron’s website includes a page dedicated to

“How to Buy” Micron’s products, including DRAM memory.

18. Micron’s semiconductor memory products are offered under, at least, the brand

name Crucial. The brand name Crucial is a registered trademark of Micron. Through its public

website, micron.com, Micron leads potential customers to crucial.com. Crucial.com is a public

website, which is accessible in the Commonwealth of Massachusetts. Through crucial.com,

customers throughout the United States, including within the Commonwealth of Massachusetts,

can buy Micron products, such as DRAM products. For example, through crucial.com a

customer in the Commonwealth of Massachusetts can order Micron DRAM memory such as

Crucial 4GB DDR4-2133 UDIMM.

19. Upon information and belief, Micron has infringed and continues to infringe the

Asserted Patents by manufacturing products using the ALD processes and materials claimed by

the Asserted Patents. Additionally, Micron has infringed and continues to infringe the Asserted

Patents by, directly or through its agents, using, offering for sale, and selling infringing products

throughout the United States, including within the Commonwealth of Massachusetts.

20. Micron has been aware of its infringing activities at least as of the filing of this

Complaint.

COUNT I

(INFRINGEMENT OF U.S. PATENT NO. 6,969,539)

21. Harvard hereby re-alleges and incorporates by reference the foregoing paragraphs

of the Complaint as if fully set forth herein.

22. On November 29, 2005, the United States Patent and Trademark Office

(“USPTO”) duly and legally issued U.S. Patent No. 6,969,539, entitled “Vapor Deposition of

Metal Oxides, Silicates and Phosphates, and Silicon Dioxide,” to inventors Roy G. Gordon, Jill


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Becker, Dennis Hausmann, and Seigi Suh (the “’539 Patent”). A true and correct copy of the

’539 Patent is attached as Exhibit A to this Complaint.

23. Upon information and belief, in violation of 35 U.S.C. § 271, Micron and its

subsidiaries have directly infringed and continue to directly infringe, either literally or under the

doctrine of equivalents, one or more claims of the ʼ539 Patent, by, without limitation, making

products using the process claimed by one or more claims of the ʼ539 Patent. Additionally,

Micron and its subsidiaries have infringed and continue to infringe the ’539 Patent, either

literally or under the doctrine of equivalents, in violation of 35 U.S.C. § 271, by, without

limitation, using, offering for sale and/or selling, those products throughout the United States,

including within the Commonwealth of Massachusetts.

24. Upon information and belief, at least certain Micron DRAM memory products are

made using a process that includes all of the limitations of one or more of the claims of the ’539

Patent. Upon information and belief, Micron makes these memory products in the United States.

Upon information and belief, Micron directly or indirectly, uses, sells, and/or offers for sale these

memory products throughout the United States, including within the Commonwealth of

Massachusetts.

25. Micron further violates 35 U.S.C. § 271(g), to the extent Micron makes DRAM

memory products using a process that includes all of the limitations of one or more of the claims

of the ’539 Patent abroad and imports them into the United States.

A. Direct Infringement of the ’539 Patent

26. Upon information and belief, certain Micron processors are made using the

process claimed by one or more claims of the ʼ539 Patent. The analysis below demonstrates how

Micron’s DRAM is made using a process claimed by one or more claims of the ʼ539 Patent. The

claim and products analyzed below are exemplary and are not intended to limit Harvard’s


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allegations. The analysis is based on information available to Harvard before discovery in this

action. Harvard reserves the right to assert any additional claims of the ’539 Patent against any

infringing acts by Micron.

1. Claim 24

27. Upon information and belief, at least Micron’s DRAM memory is made using a

process that practices each element of claim 24 of the ’539 Patent.

a. A process for forming a metal oxide, comprising:

28. Upon information and belief, Micron performs a process for forming a metal

oxide as part of its manufacturing of certain Micron DRAM memory chips.

29. DRAM memory chips are microelectronic devices that include insulators

containing metal oxide.2

30. Micron uses ALD for DRAM capacitor dielectric films.3 ALD is typically used

for DRAM capacitor dielectrics due to the required high aspect ratios.4

2 See Micron, DRAM, https://www.micron.com/products/dram; Micron, DDR4,

https://www.micron.com/products/dram/ddr4-sdram.


http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiU__Or9M_KAhXFdT4KHSIUDfIQjRwIBw&url=http://www.cbsnews.com/news/is-micron-technology-in-merger-talks/&psig=AFQjCNEW2f01jU7cPxdPENklr9LY_DnzOA&ust=1454187322997897

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31. For example, a teardown image of a Micron DRAM memory chip, shows a

capacitor dielectric that includes a zirconium oxide (ZrO2), metal oxide layer.5

High-Angle Annular Dark-Field (HAADF) image of Micron DDR4 DRAM capacitor

b. exposing a heated surface alternately to the vapor of one or more

metal amides having an amido group selected from the group

consisting of dialkylamido, disilylamido and (alkyl)(sily) amido

moieties, and then to the vapors of water or an alcohol.

32. Upon information and belief, Micron performs a process wherein a heated surface

is exposed alternately to the vapor of one or more metal amides having an amido group selected

from the group consisting of dialkylamido, disilylamido and (alkyl)(sily) amido moieties, and

then to the vapors of water or an alcohol.

3 See M. Leskelä, Industrial Applications of Atomic Layer Deposition (ALD), 10th MIICS Conference,

Mikkeli, March 18, 2010, available at http://www.miics.net/archive/getfile.php?file=162; see also Micron unveils

new DRAM blueprint, EETimes (June 16, 2004), http://www.eetimes.com/document.asp?doc_id=1150471.

4 See Clark, Robert D., Emerging Applications for High K Materials in VLSI Technology, Materials 2014,

7(4), 2913-2944, available at http://www.mdpi.com/1996-1944/7/4/2913.

5 See TECHNOLOGY ROADMAP of DRAM for Three Major manufacturers: Samsung, SK-Hynix and

Micron (Oct. 2014), available at http://www.techinsights.com/uploadedFiles/Public_Website/Content_-

_Primary/Marketing/2015/TechServices/TechInsights-DRAMRoadmap2014.ppt; see also Carl Wintgens, The 50-

nm DRAM battle rages on: An overview of Micron’s technology, EETimes (Mar. 23, 2009),

http://www.eetimes.com/document.asp?doc_id=1170601 (identifying that Micron uses zirconium oxide dielectric).


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33. The step of exposing a heated surface alternately to vapor is part of ALD, as

described by the presentation slide shown below.6

This is further illustrated by the process schematic, shown below, which shows a basic gas-flow

sequence to the chamber for Chemical Vapor Deposition and for ALD. 7

34. ALD is typically used for DRAM capacitor dielectrics due to the high aspect

ratios required.8 Micron uses ALD for DRAM capacitor dielectric films.

9 For example,

6 See Atomic Layer Deposition Overview, Ultratech/CambridgeNanotech

http://www.cambridgenanotechald.com/atomic-layer-deposition-tutorial.shtml#.

7 Clark, Robert D., Emerging Applications for High K Materials in VLSI Technology, Materials 2014, 7(4),

2913-2944, available at http://www.mdpi.com/1996-1944/7/4/2913.

8 See id.


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teardown images of Micron DRAM memory chips show a capacitor dielectric that includes a

zirconium oxide (ZrO2), metal oxide layer.10


35. In DRAM applications, “[a]lkylamides are the most commonly used precursors

for HfO2” ALD films.11

Further, tetrakis (ethyl-methylamino) zirconium is one of the “most

popular precursors…in industrial manufacturing of DRAM.”12

Thus, upon information and

belief, a heated surface is exposed to a vapor comprising tetrakis (ethyl-methylamino) zirconium,

which is a metal amide having an amido group selected from the group consisting of

dialkylamido, disilylamido and (alkyl)(sily) amido moieties.




10 See also TECHNOLOGY ROADMAP of DRAM for Three Major manufacturers: Samsung, SK-Hynix

and Micron, Oct 2014, available at http://www.techinsights.com/uploadedFiles/Public_Website/Content_-




11 Atomic Layer Deposition for Semiconductors, Hwang, Cheol Seong et. al., at 95.

http://www.springer.com/us/book/9781461480532.

12 See Wada, Senji, et.al., “Development of ALD Precursors for Semiconductor Devices”, Atomic Layer

Deposition Applications 4, ECS Transactions, Volume 16, Issue 4, pages 103-111 (2008).


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36. Further, “ALD of metal oxides involves the reaction of a metal oxide precursor

with an oxygen source. Water is the most commonly used oxygen precursor[.]”13

Thus, upon

information and belief, the heated surface is exposed to water vapor in the process performed by

Micron.

COUNT II

(INFRINGEMENT OF U.S. PATENT NO. 8,334,016)

37. Harvard hereby re-alleges and incorporates by reference the foregoing paragraphs

of the Complaint as if fully set forth herein.

38. On December 18, 2012, the USPTO duly and legally issued U.S. Patent No.

8,334,016, entitled “Vapor Deposition of Metal Oxides, Silicates and Phosphates, and Silicon

Dioxide,” to inventors Roy G. Gordon, Jill Becker, Dennis Hausmann, and Seigi Suh (“the ’016

Patent”), as a continuation of U.S. Patent No. 7,507,848, which is a continuation of the ’539

Patent. A true and correct copy of the ’016 Patent is attached as Exhibit B to this Complaint.

39. Upon information and belief, in violation of 35 U.S.C. § 271, Micron and its

subsidiaries have directly infringed and continue to directly infringe, either literally or under the

doctrine of equivalents, one or more claims of the ʼ016 Patent, including at least claims 1, 2, 7,

and 8, by, without limitation, making products using the process claimed by one or more claims

of the ’016 Patent. Micron and its subsidiaries have infringed and continue to infringe the ’016

Patent, either literally or under the doctrine of equivalents, by, without limitation, using, offering

for sale and/or selling, those products throughout the United States, including within the

Commonwealth of Massachusetts.

13

Clavel, G.; Marichy, C.; and Pinna, N., ALD of Nanostructured Materials, Chapter 4.2 - Sol-Gel and

ALD: An Overview. (2012), Wiley-VCH, page 63.


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40. Upon information and belief, at least, Micron DDR4 DRAM memory products

are made using a process that includes all of the limitations of one or more of the claims of the

’016 Patent, including at least claims 1, 2, 7, and 8. Upon further information and belief, Micron

makes these memory products in the United States. Upon information and belief, Micron,

directly or indirectly, uses, sells, and/or offers for sale these memory products throughout the

United States, including within the Commonwealth of Massachusetts.

41. Micron further violates 35 U.S.C. § 271(g) to the extent it makes DRAM memory

products using a process that includes all of the limitations of one or more of the claims of the

’016 Patent abroad and imports them into the United States.

A. Direct Infringement of the ’016 Patent

42. Upon information and belief, certain Micron processors are made using the

process claimed by one or more claims of the ʼ016 Patent, including at least claims 1, 2, 7, and 8.

The analysis below demonstrates how Micron’s DRAM is made using a process claimed by one

or more claims of the ʼ016 Patent. The claims and products analyzed below are exemplary and

are not intended to limit Harvard’s allegations. The analysis is based on information available to

Harvard before discovery in this action. Harvard reserves the right to assert any additional

claims of the ’016 Patent against any infringing acts by Micron.

1. Claim 1

43. Upon information and belief, at least, Micron’s DRAM memory chips are made

using a process that practices each element of claim 1 of the ’016 Patent.

a. A process for making an insulator in a microelectronic device, the

process comprising:

44. Upon information and belief, Micron performs a process for making an insulator

in a microelectronic device. Upon information and belief, Micron performs a process for making


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an insulator as part of its manufacturing of Micron DRAM memory chips. DRAM memory

chips are microelectronic devices that include insulators.14

45. Micron uses ALD for DRAM capacitor dielectric films.15

ALD is typically used

for DRAM capacitor dielectric films due to the high aspect ratios required.16

b. introducing a first reactant component into a deposition chamber;

46. Upon information and belief, Micron introduces a first reactant component into a

deposition chamber. The step of introducing a first reactant component into a deposition

chamber is part of ALD, as described by the presentation slide shown below.17

14

See Micron, DRAM, https://www.micron.com/products/dram; Micron, DDR4,

https://www.micron.com/products/dram/ddr4-sdram.




16 See Clark, Robert D., Emerging Applications for High K Materials in VLSI Technology, Materials 2014,



http://www.cambridgenanotechald.com/atomic-layer-deposition-tutorial.shtml#.


http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiU__Or9M_KAhXFdT4KHSIUDfIQjRwIBw&url=http://www.cbsnews.com/news/is-micron-technology-in-merger-talks/&psig=AFQjCNEW2f01jU7cPxdPENklr9LY_DnzOA&ust=1454187322997897

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This is further illustrated by the process schematic, below, which shows a basic gas flow

sequence to the chamber for Chemical Vapor Deposition and for ALD.18

47. ALD is typically used for DRAM capacitor dielectric films due to the high aspect

ratios required.19

Micron uses ALD for DRAM capacitor dielectric films.20

c. introducing a second reactant component into the deposition

chamber; and

18

Clark, Robert D., Emerging Applications for High K Materials in VLSI Technology, Materials 2014, 7(4),

2913-2944, available at http://www.mdpi.com/1996-1944/7/4/2913.

19 See id.





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48. Upon information and belief, Micron introduces a second reactant component into

a deposition chamber. The step of introducing a second reactant component into a deposition

chamber is part of ALD.21

ALD is typically used for DRAM capacitor dielectric films due to the

high aspect ratios required. Micron uses ALD for DRAM capacitor dielectric films.22

d. alternately repeating introducing the first reactant component and

the second reactant component into the deposition chamber;

49. Upon information and belief, Micron alternately repeats introducing the first

reactant component and the second reactant component into the deposition chamber. Alternately

repeating introducing the first reactant component and the second reactant component into the

deposition chamber is part of ALD.23

ALD is typically used for DRAM capacitor dielectric

films due to the high aspect ratios required. Micron uses ALD for DRAM capacitor dielectric

films.24

e. wherein deposition of the first reactant component and the second

reactant component are self-limiting;

50. Upon information and belief, Micron performs the process wherein deposition of

the first reactant component and the second reactant component are self-limiting. The process

21

See Atomic Layer Deposition Overview, Ultratech/CambridgeNanotech

http://www.cambridgenanotechald.com/atomic-layer-deposition-tutorial.shtml#; see also Clark, Robert D.,

Emerging Applications for High K Materials in VLSI Technology, Materials 2014, 7(4), 2913-2944, available at

http://www.mdpi.com/1996-1944/7/4/2913.





http://www.cambridgenanotechald.com/atomic-layer-deposition-tutorial.shtml#; see also Clark, Robert D.,

Emerging Applications for High K Materials in VLSI Technology, Materials 2014, 7(4), 2913-2944, available at

http://www.mdpi.com/1996-1944/7/4/2913.





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wherein deposition of the first reactant component and the second reactant component are self-

limiting is part of ALD.25

51. ALD is typically used for DRAM capacitor dielectric films due to the high aspect

ratios required. Micron uses ALD for DRAM capacitor dielectric films.26

f. wherein said first reactant component comprises a metal

alkylamide;

52. Upon information and belief, Micron performs the process wherein the first

reactant component comprises a metal alkylamide. Teardown images of Micron’s DRAM

memory chip show a capacitor dielectric insulator that includes a zirconium oxide layer.27

25

Clark, Robert D., Emerging Applications for High K Materials in VLSI Technology, Materials 2014,






Micron, Oct 2014, available at http://www.techinsights.com/uploadedFiles/Public_Website/Content_-



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53. Further, tetrakis (ethyl-methylamino) zirconium is one of the “most popular

precursors…in industrial manufacturing of DRAM.”28

In DRAM applications “[a]lkylamides

are the most commonly used precursors… for ZrO2” ALD films.29

Thus, upon information and

belief, the first reactant is tetrakis (ethyl-methylamino) zirconium, which is a metal alkylamide.

g. wherein said second reactant component interacts with the

deposited first reactant component to form the insulator; and

54. Upon information and belief, Micron performs a process wherein the second

reactant component interacts with the deposited first reactant component to form the insulator.

Teardown images of Micron’s DRAM memory chip show a capacitor dielectric insulator that is



28 Wada, Senji, et.al., “Development of ALD Precursors for Semiconductor Devices”, Atomic Layer





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formed by the ALD process with the second component interacting with the first reactant.30

Micron uses ALD for DRAM capacitor dielectric films.31

h. wherein said insulator comprises oxygen and the metal from the

metal alkylamide.

55. Upon information and belief, Micron performs a process wherein the insulator

comprises oxygen and the metal from the metal alkylamide. Teardown images of a Micron

DRAM chip show a capacitor dielectric insulator that includes a zirconium oxide (ZrO2), metal

oxide layer. The zirconium oxide layer includes oxygen and the zirconium metal from the metal

alkylamide.32


30

See TECHNOLOGY ROADMAP of DRAM for Three Major manufacturers: Samsung, SK-Hynix and














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56. Further, tetrakis (ethyl-methylamino) zirconium is one of the “most popular

precursors…in industrial manufacturing of DRAM.”33

Thus, upon information and belief, the

metal (zirconium) is from tetrakis (ethyl-methylamino) zirconium, which is a metal alkylamide.

2. Claim 2



a. The process as in claim 1, wherein the insulator insulates a gate or

a capacitor.

58. Upon information and belief, Micron performs the process of claim 1, wherein the

insulator insulates a gate or a capacitor. For example, teardown images of Micron’s DRAM

memory chip show a capacitor dielectric insulator that includes a zirconium oxide layer.34


33

Wada, Senji, et.al., “Development of ALD Precursors for Semiconductor Devices”, Atomic Layer

Deposition Applications 4, ECS Transactions, Volume 16, Issue 4, pages 103-111 (2008); see also Atomic Layer

Deposition for Semiconductors, Hwang, Cheol Seong et. al., at 95.








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3. Claim 7



a. The process as in claim 2, wherein the metal alkylamide is a

zirconium dialkylamide.


metal alkylamide is a zirconium dialkylamide. For example, tetrakis (ethyl-methylamino)

zirconium is one of the “most popular precursors…in industrial manufacturing of DRAM.”35

In

DRAM applications “[a]lkylamides are the most commonly used precursors… for ZrO2” ALD

films.36

Thus, upon information and belief, the metal alkylamide is tetrakis(ethyl-

methylamino)zirconium, which is a zirconium dialkylamide.

4. Claim 8



a. The process as in claim 7, wherein the zirconium dialkylamide is

tetrakis (ethylmethylamido) zirconium.


zirconium dialkylamide is tetrakis (ethylmethylamido) zirconium. For example, tetrakis (ethyl-

methylamino) zirconium is one of the “most popular precursors…in industrial manufacturing of

DRAM.”37

In DRAM applications “[a]lkylamides are the most commonly used precursors… for

35

Wada, Senji, et.al., “Development of ALD Precursors for Semiconductor Devices”, Atomic Layer




37 Wada, Senji, et.al., “Development of ALD Precursors for Semiconductor Devices”, Atomic Layer



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ZrO2” ALD films.38

Thus, upon information and belief, the zirconium dialkylamide reactant is

tetrakis (ethylmethylamido) zirconium.

PRAYER FOR RELIEF

WHEREFORE, Harvard requests that the Court grant the following relief:

A. A finding that Micron has directly infringed the Asserted Patents;

B. An award to Harvard of royalty or lost-profit based damages adequate to

compensate it for Micron’s infringement of the ʼ539 and ʼ016 patents, such

damages to be determined by a jury;

C. A permanent injunction against Micron, its officers, agents, employees, and those

persons in active concert or participation with it or any of them, and its successors

and assigns, from continued acts of infringement of the Asserted Patents,

including but not limited being enjoined from making, using, selling, and/or

offering for sale within the United States, and/or importing into the United States,

any products that infringe the Asserted Patents; and

D. An award to Harvard of such other and further relief as this Court deems just and

proper.

DEMAND FOR JURY TRIAL

Plaintiff hereby demands a jury in accordance with Rule 38 of the Federal Rules of Civil

Procedure.

38

Atomic Layer Deposition for Semiconductors, Hwang, Cheol Seong et. al., at 95.



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Dated: 6/24/2016

Respectfully submitted,

/s/ William Belanger

William Belanger

Massachusetts Bar No. 657184

Alison McCarthy

Gregory D. Len

Maia H. Harris

Griffin Mesmer

Pepper Hamilton LLP

19th Floor, High Street Tower

125 High Street

Boston, MA 02110-2736

Telephone: 617.204.5100

Facsimile: 617.204.5150

Email: [email protected]

Counsel for President and Fellows of

Harvard College


EXHIBIT A

Case 1:16-cv-11249 Document 1-1 Filed 06/24/16 Page 1 of 22

(12) United States Patent Gordon et al.

US006969539B2

US 6,969,539 B2 Nov. 29, 2005

(10) Patent N0.: (45) Date of Patent:

(54) VAPOR DEPOSITION OF METAL OXIDES, SILICATES AND PHOSPHATES, AND SILICON DIOXIDE

(75) Inventors: Roy G. Gordon, Cambridge, MA (US); Jill Becker, Cambridge, MA (US); Dennis Hausmann, Los Gatos, CA (US); Seigi Suh, Pleasanton, CA (US)

(73) Assignee: President and Fellows of Harvard College, Cambridge, MA (US)

( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.

(21) Appl. No.: 10/381,628

(22) PCT Filed: Sep. 28, 2001

(86) PCT No.: PCT/US01/30507

§ 371 (6X1), (2), (4) Date: Sep. 2, 2003

(87) PCT Pub. No.: WO02/27063

PCT Pub. Date: Apr. 4, 2002

(65) Prior Publication Data

US 2004/0043149 A1 Mar. 4, 2004

Related US. Application Data (60) Provisional application No. 60/236,283, ?led on Sep. 28,

2000, and provisional application No. 60/253,917, ?led on Nov. 29, 2000.

(51) Int. Cl.7 .............................................. .. C23C 16/40

(52) US. Cl. ............................ .. 427/255.29; 427/255.38

(58) Field of Search ...................... .. 427/255.29, 255.38

(56) References Cited

U.S. PATENT DOCUMENTS

4,386,117 A * 5/1983 Gordon .................... .. 427/109

4,474,642 A * 10/1984 Nakane et al. ............ .. 438/669

(Continued)

FOREIGN PATENT DOCUMENTS

DE 43/16883 11/1994 EP 0560617 9/1993 EP 1067595 A2 1/2001 EP 1067595 A3 1/2002 JP 04359515 11/1992 JP 2002093803 A2 3/2002 JP 2002093804 A2 3/2002 WO 97/38355 10/1997 WO 98/15669 4/1998 WO 99/29924 6/1999 WO 99/29926 6/1999 WO WO-01/27347 4/2001 WO 01/45158 6/2001 WO 02/27063 4/2002

OTHER PUBLICATIONS

Lee, et al., “Mass Production Worthy HfO2—Al2O3 Laminate Capacitor Technology using Hf Liquid Precursor for Sub—100nm DRAMs,” Presented at IEEE IEDM (Interna tional Electronic Devices Meeting), San Francisco, CA, Dec. 9—11 (2002), pp 1—4.

(Continued)

Primary Examiner—Bret Chen (74) Attorney, Agent, or Firm—Wilmer Cutler Pickering Hale and Dorr LLP

(57) ABSTRACT

Metal silicates or phosphates are deposited on a heated substrate by the reaction of vapors of alkoxysilanols or alkylphosphates along With reactive metal amides, alkyls or alkoxides. For example, vapors of tris-(ter-butoxy)silanol react With vapors of tetrakis(ethylmethylamido)hafnium to deposit hafnium silicate on surfaces heated to 300° C. The product ?lm has a very uniform stoichiometry throughout the reactor. Similarly, vapors of diisopropylphosphate react With vapors of lithium bis(ethyldimethylsilyl)amide to deposit lithium phosphate ?lms on substrates heated to 250° C. supplying the vapors in alternating pulse produces these same compositions With a very uniform distribution of thickness and excellent step coverage.

31 Claims, 3 Drawing Sheets

K140 K150


US 6,969,539 B2 Page 2

US. PATENT DOCUMENTS

4,723,978 A * 2/1988 Clodgo et al. .............. .. 216/55

4,792,463 A 12/1988 Okada et 211. 5,389,401 A 2/1995 Gordon 5,403,630 A 4/ 1995 Matsui et al. 5,710,075 A 1/1998 Tseng 5,922,787 A * 7/1999 Kondo et al. ............. .. 523/122

6,090,442 A 7/2000 Klaus et al. 6,335,288 B1 1/2002 KWan et 211. 6,339,004 B1 1/2002 Kim 6,342,432 B1 1/2002 Wang 6,395,209 B2 * 5/2002 Yoshida et al. ........... .. 264/137

6,534,395 B2 3/2003 Werkhoven et al. 6,867,152 B1 3/2005 Hausmann et al.

2002/0004281 A1 2002/0018849 A1 2002/0102814 A1 2003/0015764 A1 2004/0018694 A1

OTHER PUBLICATIONS

1/2002 Lee et al. 2/2002 George et al. 8/2002 Olsen 1/2003 Raaijmakers et al. 1/2004 Lee et al.

Park, et al., “Mass—Productive Ultra—LoW Temperature ALD SiO2 Process Promising for Sub—90nm Memory and Logic Devices,” Presented at IEEE IEDM (International Electron Devices Meeting), San Francisco, CA, Dec. 9—11 (2002), pp 1—4. Coltrin, et al., “Chemical kinetics in chemical vapor depo sition: groWth of silicon dioxide from tetraethoxysilane (TEOS),” Thin Solid Films, vol. 365, pp. 251—263 (2000). Ikeda, et al., “OZone/Organic—Source APCVD for USLI Re?oW Glass Films,” NEC Research & Development, No. 94, pp. 1—7 (1989). Hausmann, et al., “Rapid Vapor Deposition of Highly Con formal Silica Nanolaminates,” Science, vol. 298, pp. 402—406 (2002). Kingon, et al., “Alternative dielectrics to silicon dioxide for memory and logic devices,” Nature, vol. 406, pp. 1032—1038, (2000). Ritala, “Advanced ALE processes of amorphous and poly crystalline ?lms,” Applied Surface Science, vol. 112, pp. 223—230, (1997). Ritala, et al., “Atomic Layer Deposition of Oxide Thin Films With Metal Alkoxides as Oxygen Sources,” Science, vol. 288, pp. 319—321, (2000).

Backer, et al., “Esters Mixtes De L’Acide Tetrathio Ortho silicique,” Rec. Trav. Chim., vol. 61, pp. 500—512, (1942). Okamoto, et al., “Convenient Synthetic Route To Mono—Or Dialkyl Phosphate From Inorganic Phosphorus Acids,” Phosphorus, Sulfur and Silicon, vol. 55, pp. 195—200 (1991). McIvor, et al., “Preparation and Toxicity of Some Alkyl Thiopyrophosphates,” Canadian J. Chemistry, vol. 34, pp. 1825—1827 (1956). ZWierZak, et al., “Organophosphorus Esters—tButylAs Pro tecting Group In Phosphorylation Via Nucleophilic Dis placement,” Tetrahedron, vol. 27, pp. 3163—3170 (1971). George, et al., “Atomic Layer Controlled Depositon of SiO2 and AI203 Using ABAB . . . binary reaction sequence

chemistry,” Appl. Surf Sci., 82/83, pp. 460—467 (1994). Gasser, et al., “Qusai—Monolayer Deposition of Silicon Dioxide,” Thin Solid Films, vol. 250, pp. 213—218 (1994). Klaus, et al., “Atomic Layer Deposition of SiO2 at Room Temperature Using NH3—catalyZed Sequential Surface Reactions,” Surf Sci., vol. 447, pp. 81—90 (2000). Ferguson, et al., “Atomic Layer Deposition of A1203 and SIO2 on BN Particles Using Sequential Surface Reactions,” Applied Surface Science, vols. 162—163, pp. 280—292, (2000). Yamaguchi, et al., “Atomic Layer Chemical—Vapor—Depo sition of Silicon Dioxide Films With an Extremely LoW Hydrogen Content,” Applied Surface Science, vols. 130—132, pp. 202—207 (1998). Morishita, et al., “NeW Substances for Atomic—Layer Depo sition of Silicon Dioxide,” J. Non—Crystalline Solids, vol. 187, pp. 66—69 (1995). Klaus, et al., “Atomic Layer Deposition of SiO2 Using CatalyZed and UncatalyZed Self—Limiting Surface Reac tions,” Surface Review and Letters, vol. 6(3), pp. 435—448 (1999). Ferguson, et al., “Atomic Layer Deposition of SiO2 Fims on BN Particles Using Sequential Surface Reactions,” Chem. Mater, vol. 12, pp. 3472—3480 (2000).

* cited by examiner


U.S. Patent Nov. 29,2005 Sheet 1 of3 US 6,969,539 B2

.---.Aw ........................ -. 8 M

M a M “HT m H? M

iw? m :K . _ mm | m _ 5K Mm 2‘ m

m 2T\ M

2:\ [w


U.S. Patent Nov. 29,2005 Sheet 2 of3 US 6,969,539 B2


US 6,969,539 B2 1

VAPOR DEPOSITION OF METAL OXIDES, SILICATES AND PHOSPHATES, AND

SILICON DIOXIDE

RELATED APPLICATIONS

This application claims priority under 37 CFR §1.119 (e) from copending application Ser. Nos. 60/236,283, ?led Sep. 28, 2000 entitled “Vapor Deposition of Metal Silicates and Phosphates” and 60/253,917, ?led Nov. 29, 2000, entitled “Vapor Deposition of Metal Oxides, Silicates and Phosphates, and Silicon Dioxide”.

STATEMENT AS TO FEDERALLY SPONSORED RESEARCH

This invention Was made With the support of the United States government under National Science Foundation Grant No. ECS-9975504. The United States may have certain rights in the invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention This invention relates to novel reagents for use in thin ?lm

deposition processes such as chemical vapor deposition (CVD) and atomic layer deposition These reagents can be used for deposition of materials containing silicon and/or phosphorus along With metals and/or oxygen, com monly called metal oxides, silicates or metal phosphates, or silicon dioxide.

2. Description of the Related Art Chemical vapor deposition (CVD) is a Widely-used pro

cess for forming solid materials, such as coatings or poWders, from reactants in the vapor phase. Comprehensive revieWs of CVD processes have been given recently in C VD of Nonmetals, W. S. Rees, Jr., Editor, VCH Publishers, Weinheim, Germany, 1996; CVD of Compound Semiconductors, A. C. Jones and P. O’Brien, VCH, 1996; and The Chemistry of Metal CVD, T. Kodas and M. Hampden-Smith, Editors, VCH, 1994.

In CVD processes, a reactant vapor or vapor mixture is brought into contact With a heated surface on Which a thin ?lm is deposited. In a related form of CVD, tWo reactant vapors are alternately exposed to the heated surface. This

form of CVD is often called atomic layer deposition For suitable reactants, ALD can provide improved step

coverage and thickness uniformity compared to CVD With mixed vapors. For a revieW of ALD, see the paper by Mikko Ritala in Applied Surface Science, volume 112, pages 223—230 (1997).

Coatings of metal silicates have many applications or potential applications. For example, silicates of Zirconium, hafnium, yttrium or lanthanum are being considered as potential replacements for silicon dioxide in gate insulators in silicon semiconductor technology. See, for example, A. Kingon et al., Nature, volume 406, pages 1032—1038 (2000). In Science, (volume 288, pages 319 to 321 (2000)), Ritala et al. report the use of the sequential ALD reaction of metal chlorides and silicon alkoxides to produce metal silicates, including Zirconium silicate. HoWever, this reaction deposits ?lms containing residual chlorine, Which can be deleterious to the properties of the ?lm or to its adhesion to substrates or subsequent coatings. The chlorine in the precursors can also corrode metal substrates or the apparatus used for the deposition. Thus it Would be advantageous to have chlorine free precursors for CVD or ALD of metal silicates or oxides.

ALD of silicon dioxide has been achieved by Klaus et al., US. Pat. No. 6,090,442 (2000), but the deposition rate is

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2 very sloW and the substrate temperature is limited to values near room temperature.

Lithium phosphate is a material of current interest as a lithium ion conductor in lithium batteries. Currently there is no knoWn process for CVD or ALD of lithium phosphate.

SUMMARY OF THE INVENTION

A principal feature of the present invention includes volatile chemical precursors With reactivity adapted for CVD or ALD of metal silicates, phosphates or oxides. An advantage of these chemical precursors is that they do

not contain chlorine, and leave no chlorine residue during a process for the CVD or ALD of metal silicates, phosphates or oxides.

A related feature of the present invention is the deposition of metal silicates under conditions that produce a sharp interface betWeen silicon substrates and the deposited metal silicate.

An advantage of the process is that it permits deposition of materials containing metal silicates or phosphates by a CVD process in Which all the reactants may be mixed homogeneously before delivery to the heated surface of the substrate.

An additional advantage of the process is the vapor deposition of metal silicates or phosphates With relatively ?xed ratio of metal to silicon over a range of conditions such as concentrations of reactants and position of the substrate inside the reactor.

Another advantage of the invention is its ability to make conformal coatings over substrates With narroW holes, trenches or other structures. This ability is commonly known as good step coverage. Another feature of the present invention is the preparation

of material comprising lithium phosphate. An advantage of the invention is that the reactants are

stable and relatively nonhaZardous. Another feature of the invention includes a chemical

vapor deposition or atomic layer deposition process for metal oxides or mixtures of metal oxides. A further feature of the invention includes process for

atomic layer deposition of silicon dioxide. One particular feature of the present invention includes a

process for depositing oxides or silicates of Zirconium, hafnium, yttrium and/or lanthanum having high dielectric constants of use as gate insulators or trench capacitors in microelectronic devices.

Another particular feature of the present invention includes a process for depositing silicon dioxide or metal silicates having useful optical properties, such as in planar Waveguides and multiplexers/demultiplexers, and in optical interference ?lters. An additional feature of the present invention includes a

process for depositing lithium phosphate coatings alloWing rapid diffusion of lithium for use as separators in batteries or electrochromic devices.

Other features and advantages of the invention Will be obvious to those skilled in the art on reading the instant invention.

In one aspect of the invention vapors of alkoxysilanols are reacted With the vapors of suitably reactive metal or metal loid compounds, such as metal or metalloid alkylamides, alkyls or cyclopentadienyls, to form metal silicates. The reaction may be carried out in a manner to form ?lms.

In at least some embodiments, tris(alkoxy)silanol com pounds have the general formula 1, in Which R” represents


US 6,969,539 B2 3

hydrogen, alkyl groups, ?uoroalkyl groups or alkyl groups substituted With other atoms or groups, preferably selected to enhance the volatility of the compound, Where R” is any one of R1 through R” The R” may be the same or different from each other.

In at least some embodiments methyl groups are selected for each of the R” in the general formula 1 given above one obtains a highly preferred compound tris(tert-butoxy)silanol 2, Which may be Written more compactly as (’BuO)3SiOH.

2 CH3

CH3

Another compound of the invention is tris(tert-pentyloxy) silanol, also knoWn as tris(tert-amyloxy)silanol 3, Which may be Written more compactly as (’AmO)3SiOH.

In at least some embodiments of the invention Di(alkoxy) silanediols such as (’BuO)2Si(OH)2 can also be used, although they are less stable than tris(alkoxy)silanol com pounds in at least some applications. Di(alkoxy)silanediol compounds having the general formula 4 may be used according to the invention, Where R”, represents hydrogen, alkyl groups, ?uoroalkyl groups or alkyl groups substituted by other atoms or groups, preferably selected to enhance volatility and stability, and may be the same or different for any R”, and R” is any of R1 through R6 may be the same or different.

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R6 OH

In at least some embodiments, the groups R1 for the general formula 1 or R1—R6 for the general formula 4 may be selected from the group consisting of hydrogen, methyl, ethyl, n-propyl and isopropyl groups.

In the foregoing compounds, it is also understood that the alkyl groups R1 through R9 for general formula or R1 through R6 for general formula 4 may be a hydrocarbon having some degrees of unsaturation, e.g., aryl, alkenyl or alkynyl groups.

In at least some embodiments, metal compounds include those that react readily With the slightly acidic protons in silanols. These acidic protons are the ones attached directly to oxygen in the silanol. Metal compounds that generally react With these acidic protons include most metal alkyls and other organometallic compounds, metal alkylamides, and some metal alkoxides. The reactivity of any particular compound can be established readily by mixing it With an alkoxysilanol and analyzing the mixture for products by techniques such as nuclear magnetic resonance (NMR). We have found that compounds that are knoWn to react With Water also generally react With alkoxysilanols.

We have also discovered that the stoichiometry of the deposited metal silicates can be controlled. The silicon/ metal ratio may be decreased by replacing some or all of the silanol With Water or an alcohol. Conversely, the silicon/ metal ratio may be increased by replacing some or all of the metal source by a suitably reactive silicon-containing com pound such as a silicon amide or a silylene. By these methods the composition of the deposited material may be chosen to be any composition from pure metal oxide to pure silicon dioxide or any desired silicon/metal ratio in betWeen. The stoichiometry may even be varied during the course of one deposition. For example, in the deposition of a gate insulator for a silicon semiconductor device, it may be desirable to begin the deposition With a silicon-rich layer close to the silicon surface in order to improve the electrical properties of the interface, folloWed by a metal-rich layer With higher dielectric constant.

In another aspect of the invention, vapors of bis(alkyl) phosphates are reacted With the vapors of reactive metal compounds, such as metal alkylamides, metal alkyls, metal cyclopentadienides or metal alkoxides, to form metal phos phates. The reaction may be carried out in a Way that forms ?lms.

In at least some embodiments of the invention, phosphorus-containing precursors include bis(alkyl) phosphates 5 in Which R”, represents hydrogen, alkyl groups, ?uoroalkyl groups or alkyl groups, substituted With other atoms or groups Where R” may be any of R1 through R6. The R” may be the same or different from each other.


US 6,969,539 B2

In at least one embodiment, the phosphorus precursor is diisopropylphosphate, represented by the formula 6.

H

It is also possible to control the stoichiometry of the metal phosphates. The phosphorus/metal ratio may be decreased by replacing some or all of the bis(alkyl)phosphate With Water or an alcohol. Conversely, the phosphorus/metal ratio may be increased by replacing some or all of the metal source by a suitably reactive phosphorus source. By these methods, the composition of the deposited material may be varied from pure metal oXide to pure phosphorus oXide or any desired phosphorus/metal ratio.

In at least some embodiments, the groups R1—R6 for the general formula 5 may be selected from the group consisting of hydrogen, methyl, ethyl, n-propyl or isopropyl groups. In the foregoing compounds, it is also understood that the alkyl groups R1 through R9 for general formula 1 or R1 through R6 for general formula 4 may be a hydrocarbon having some degrees of unsaturation, e.g., aryl, alkenyl or alkynyl groups.

In another aspect of the invention, a process for preparing a material comprising silicon includes eXposing a substrate to one or more vapors chosen from the group consisting of alkoXysilanols, alkoXysilanediols and silylenes. In at least some embodiments, the silylene is the compound described by the formula

Where R is an alkyl group, or R is tert-butyl. In one aspect of the invention, a process for forming a

material including phosphorus includes eXposing a substrate to one or more vapors chosen from the group consisting of bis(alkyl)phosphates, phosphorus(III) oXide and White phos phorus.

In another aspect of the invention, a process is provided for preparing oxygen-containing materials including eXpos ing a substrate to one or more vapors chosen from the group

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6 consisting of arene hydrates, such as benZene hydrate, naphthalene hydrate, or a substituted benZene hydrate or a substituted naphthalene hydrate.

In another aspect of the invention, a process for forming a metal oXide is provided including eXposing a heated surface alternately to the vapor of one or more metal amides and then to the vapors of Water or an alcohol.

In at least some embodiments, the alcohol is an arene hydrate, or in at least some embodiments, the metal amide or amides are chosen from Table 1.

In another aspect of the invention, a process for forming material including oXygen and one or more metals is pro vided by eXposing a surface alternately to the vapor of one or more organometallic compounds and to the vapor of an arene hydrate.

In at least one embodiment, the organometallic com pounds are chosen from Table 2.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, features, and advantages of the present invention can be more fully appreciated With reference to the folloWing detailed description of the invention When con sidered in connection With the folloWing draWings. The draWings are presented for the purpose of illustration only are not intended to be limiting of the invention, in Which:

FIG. 1 is a cross-sectional illustration of an atomic deposition layer apparatus used in the practice of at least one embodiment of the invention;

FIG. 2 is a cross-sectional illustration of an atomic deposition layer apparatus used in the practice of at least one embodiment of the invention; and

FIG. 3 is a cross-sectional scanning electron micrograph of holes in a silicon Wafer uniformly coated With hafnium dioxide using one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

1. Metal Silicates and Silicon Dioxide. The present invention provides a method for preparing

metal silicates of varying metal and silicon content. The method involves the reaction of a vapor of an alkoXysilanol or alkoXysilanediol With a vapor of one or more metal or metalloid compounds. The compound may be formed as a poWder or as a ?lm on a substrate, and in some embodiments, on a heated substrate. The compound may be formed on a substrate by miXing the vapors of the alkoX ysilanol or alkoXysilanediol and the metal or metalloid compound prior to deposition on a substrate. In at least some embodiments, a substrate is alternately eXposed to a alkoX ysilanol or alkoXysilanediol vapor and a vapor of one or more of a metal or metalloid compound.

Silanol and silanediol reactants are commercially avail able or may be prepared using conventional or knoWn techniques. Silicon precursor, tris(tert-butoXy)silanol, is commercially available from Aldrich Chemical Company (Milwaukee, Wis.) and Gelest, Inc. (TullytoWn, Pa.). Tris (tert-butoXy)silanol may be prepared as folloWs. First tris (tert-butoXy)chlorosilane is made by either of the folloWing tWo reactions:

The tris(tert-butoXy)chlorosilane is then hydrolyZed accord ing to the reaction


US 6,969,539 B2 7

See, Backer et al., Rec. Trav. Chim., volume 61, page 500 (1942). This compound is a solid at room temperature and melts at about 66° C. It sublimes at room temperature at a low pressure of about 10-4 Torr, and can be distilled at a temperature of about 104° C. at a pressure of 20 Torr. It is highly soluble in organic solvents such as mesitylene or tetradecane, so that its vapors can be formed conveniently by ?ash vaporiZation of its solution.

Other tris(tert-alkoxy)silanols may be prepared by similar reactions, by substituting other tertiary alcohols, such as tert-pentyl alcohol (also knoWn as tert-amyl alcohol), for tert-butanol. Tris(tert-amyloxy)silanol, (’AmO)3SiOH, is a liquid at room temperature, so its vapors can be formed conveniently by ?ash vaporiZation of the neat liquid. It has a vapor pressure of about 2 Torr at 96° C. It is commercially available from Aldrich Chemical Company.

Silanols and silanediols may be reacted With a metal source to obtain a metal silicate. The metal source may contain one or more metals and the resultant metal silicate may contain one or more metals, In at least some

embodiments, metal compounds include those that react readily With the slightly acidic protons in silanols. These acidic protons are the ones attached directly to oxygen in the silanol. Metal compounds that generally react With these acidic protons include most metal alkyls and other organo metallic compounds, metal alkylamides, and some metal alkoxides. The reactivity of any particular compound can be established readily by mixing it With an alkoxysilanol and analyZing the mixture for products by techniques such as nuclear magnetic resonance (NMR). We have found that compounds that are knoWn to react With Water also generally react With alkoxysilanols.

The reaction is carried out in the vapor state and may be carried out using CVD or ALD techniques. As is discussed in greater detail beloW, ALD provides control over the deposition process and is suitable for use in a Wide range of reaction conditions and reactant reactivity.

The silicon/metal ratio may be increased by replacing some or all of the metal precursor by a suitably reactive silicon compound. Silicon halides such as silicon tetrachloride, SiCl4, may be used to increase the silicon content, but they may leave chloride as an impurity in the product, and their reactions may be sloWer than desired. Silicon amides such as tetraisocyanatosilane, tetrakis (dimethylamido)silane or tris(dimethylamido)silane avoid the halogen contamination. HoWever, their deposition rates may also be sloWer than desired. Silylenes are more rapidly reactive. For example, the thermally stable silylene 7

Where R is an alkyl group or, in at least some embodiments, is tert-butyl, can be used as a rapidly reacting silicon source in place of part or all of the metal source, in order to increase the silicon/metal ratio.

In at least some embodiments, pure silicon dioxide may be prepared. In an ALD system, a pulse of silylene is folloWed by a pulse of oxygen gas, in order to fully oxidiZe the silylene after it has reacted With the surface. Pure silicon dioxide can be deposited rapidly by repeating the pulse sequence of silylene and oxygen. 2. Metal Phosphate and Phosphorus Oxide.

The present invention provides a method for preparing metal phosphates of varying metal and phosphorus content.

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8 The method involves the reaction of a vapor of an bis(alkyl) phosphate With a vapor of one or more metal or metalloid compounds. The compound may be formed as a poWder or as a ?lm on a substrate, and in some embodiments, on a heated substrate. The compound may be formed on a sub strate by mixing the vapors of the bis(alkyl)phosphate and the metal or metalloid compound prior to deposition on a substrate. In at least some embodiments, a substrate is alternately exposed to a bis(alkyl)phosphate vapor and a vapor of one or more of a metal or metalloid compound.

Bis(alkyl)phosphate reactants are commercially available or may be prepared using conventional or knoWn tech niques. Phosphorus precursor, diethylphosphate, is commer cially available from a number of chemical companies, including Fisher Scienti?c (Pittsburgh, Pa.) and PfaltZ and Bauer (Waterbury, Conn.). Diethylphosphate may be pre pared by the air oxidation of phosphinic acid in ethanol, catalyZed by copper chloride:

See, Y. Okamoto, T. Kusano and S. Takamuku, Phosphorus, Sulfur and Silicon, volume 55, pages 195—200 (1991). An alternative reaction sequence is shoWn for diisopro

pylphosphate and may be used for other precursor com pounds by appropriate substitutions for isopropanol.

(7)

See, Mclvor et a1., Canadian]. Chemistry, volume 34, pages 1825 and 1827.

Diisopropylphosphate may also be prepared by ?rst form ing its potassium salt by the folloWing tWo reactions:

(9)

See, A. ZWierak and M. Kiuba, Tetrahedron, volume 27, pages 3163 to 3170 (1971). The analogous sodium salt may be prepared by the folloW ing tWo reactions:

The precursor diisopropylphosphate may then be liberated from its alkali salt by reaction With hydrochloric acid:

The above bis(alkyl)phosphates react With a Wide range of metal compounds to form metal phosphates. Metal com pounds that generally react With the acid phosphate protons include most metal alkyls and other organometallic compounds, metal alkylamides, and some metal alkoxides. The reactivity of any particular compound can be estab lished readily by mixing it With a bis(alkyl)phosphate and analyZing the mixture for products by techniques such as nuclear magnetic resonance (NMR). The reaction is carried out in the vapor state and may be

carried out using CVD or ALD techniques. As is discussed in greater detail beloW, ALD provides control over the deposition process and is suitable for use in a Wide range of reaction conditions and reactant reactivity. The phosphorus/metal ratio may be increased by replac

ing some or all of the metal precursor by a suitably reactive


US 6,969,539 B2 9

phosphorus compound. Phosphorus halides such as phos phorus trichloride, PCl3, phosphorus pentachloride, PClS, or phosphorus oxychloride, POCl3, may be used, but some halogen impurity may be included in the ?lm Phosphorus

10 phosphorus or phosphorus(III) oxide generally are folloWed by a pulse of oxygen in order to form fully oxidiZed ?lms.

The phosphorus/metal ratio of material made by ALD may be decreased by replacing some of the phosphorus

alkylamides such as hexamethylphosphorus triamide, 5 doses by doses of Water or alcohol. (Me2N)3P, hexamethylphosphorimidic triamide, (MeZN) 3. Metal Amides, Metal Alkyls and Metal Alkoxides. 3P=NH, or hexamethylphosphoramide, (Me2N)3PO, avoid In at least some embodiments, metal or metalloid amides the halogen contamination, but their reactions may be sloW. are useful in the practice of this invention. Some examples White phosphorus, P4, and phosphorus(III) oxide, P406, are are given in Table 1, as Well as a commercial source and/or more quickly reactive and can be used to increase the 10 literature references for their synthesis. The metalloids phosphorus/metal ratio in an ALD process. Doses of White referred to in Table 1 are boron, silicon and arsenic.

TABLE 1

Some Volatile Metal or Metalloid Amides

Melt. Pt. Vapor Press. Compound O C. O C./I‘orr Reference and/or commercial source

Al(N(SiMe3)2)3 188 Wannagat, J. Organomet. Chem. 33, 1 (1971)

Al2(NEt2)6 liquid Barry & Gordon, 2000 Al2(NEtMe)6 liquid 100/025 Barry & Gordon, 2000 Al(NiPr2)3 56-59 Brothers, Organometallics 13, 2792 (1994) Al2(NMe2)6 88-89 90/0.1 Ruff, JACS 83, 2835 (1961) Al(N(Et)CH2CH2N liquid 65—70/0.3 Barry, Gordon & Wagner, Mat. Res. Soc. Me2)(NMe2)2 Symp. Proc. 606, 83-89 (2000) As(NMe2)3 -53 55/10 Cowley, JACS 95, 6505 (1973) As(N(Me)(SiMe3))3 11-13 67—70/0.1 Birkofer & Ritter, Chem. Ber. 93, 424

(1960) B(NMe2)3 —10 39/10 Abel et al., J. Chem. Soc. 1964, 5584 B(NEt2)3 95/11 Abel & Armitage J. Organomet. Chem. 5,

326 (1966) Ba(N(SiMe3)2)2 >150 Westerhauser, Inorg. Chem. 30, 96 (1991) Be(NMe2)2 88-90 175/760 Anderson, JACS 74, 1421 (1952) Be(N(SiMe3)2)2 —5, liquid 110/3 Clark & Haaland, Chem. Commun, 1969,

912

Be(TMPD)2 —10, liquid 106/0.001 Noeth & Schlosser, Inorg. Chem. 22, 2700 (1983)

Bi(N(SiMe3)2)3 90 Lappert, J. Chem. Soc., Dalton, 2428 (1980)

Bi(N(Me)(SiMe3))3 90—92/0.1 Birkofer & Ritter, Chem. Ber. 93, 424 (1960)

Ca(N(SiMe3)2)2 >120 Lappert, J. Chem. Soc., Chem. Comm., 1141 (1990)

Cd(N(SiMe3)2)2 liquid Burger, Wannagat, J. Organomet. Chem. 3, 11 (1965)

Cd(N‘BuSiMe3)2 Fisher & Alyea, Polyhedron 3, 509 (1984) Cd(I‘MPD)2 Fisher & Alyea, Polyhedron 3, 509 (1984) Ce(N(SiMe3)2)3 95-100/10’4 Bradley, J. Chem. Soc., Dalton 1973, 1021 Ce(NiPr2)3 AngeW. Chem., Int. Ed. Engle. 36,

2480 (1997) Co(N(SiBuMe2)2)2 liquid 146/0085 Broomhall-Dillard & Gordon, 1999 Co(N(SiEtMe2)2)2 liquid 106/0.05 Broomhall-Dillard & Gordon, 1999 Co(N(SiMe3)2)2 >70 50-70/0.01 Chisholm, CVD 1, 49 (1995) Co(N(SiMe3)2)3 86-88 Power, JACS 11, 8044 (1989) Co(N(SiPrMe2)2)2 liquid 106/0.05 Broomhall-Dillard & Gordon, 1999 Cr(N(SiMe3)2)3 120 80/0.005 Bradley, J. Chem. Soc., Dalton 1972, 1580 Cr(NEt2)4 liquid 40-60/10’3 Bradley, Proc. Chem. Soc., London

1963, 305 Cr(NiPr2)3 Bradley & Chisholm, Chem. Comm. 1968, 495 Cr(NMe2)4 Bradley J. Chem. Soc. A, 1971, 1433 Cu4(N(SiMe3)2)4 >180(d.) 160/0.1 Chisholm, CVD 1, 49 (1995) Er(N(SiMe3)2)3 150-180 Wolczanski, Inorg. Chem. 31, 1311 (1992) Eu(N(SiMe3)2)3 160-162 82-84/10’4 Bradley, Chem. Comm. 1972, 349 Fe(N(SiBuMe2)2)2 liquid 130/0.2 Broomhall-Dillard & Gordon, 1999 Fe(N(SiMe3)2)2 5, liquid 80-90/0.01 Chisholm, CVD 1, 49 (1995) Fe(N(SiMe3)2)3 >80 80/0.005 Bradley, J. Chem. Soc., Dalton 1972, 1580 Ga(NMe2)3 91 125/001 Chemat Catalog, Northridge, CA Ga(NEt2)3 Chemat Catalog, Northridge, CA Ga(N(SiMe3)2)3 187 Wannagat, J. Organomet. Chem. 33, 1

(1971) Ga(N1BuSiMe3)3 174-176 CoWley, Inorg. Chem. 33, 3251 (1994) Ga(TMPD)3 130-132 CoWley, Inorg. Chem. 33, 3251 (1994) Ga(N(Me)CH2CH2 liquid 48—55/0.18 Barry, Gordon & Wagner, Mat. Res. Soc. NMe2)(NMe2)2 Symp. Proc. 606, 83-89 (2000) Gd(N(SiMe3)2)3 160-163 80-83/1074 Bradley, Chem. Comm. 1972, 349 Ge(N(SiMe3)2)2 33 60/0.04 Chisholm, CVD 1, 49 (1995)


11 US 6,969,539 B2

12

TABLE l-continued


Melt. Pt. Vapor Press. Compound ° C. O C./I‘orr Reference and/or commercial source

Ge(NEt2)4 >109 109/2 Chemat Catalog, Northridge, CA Ge(NMe2)4 14, liquid 203/760 Abel, J. Chem. Soc. 1961, 4933; Chemat Ge(N‘Bu2)2 2, liquid Lappert, J. Chem. Soc., Chem. Com. 13, 621

(1980) Ge(N1BuSiMe3)2 22 50/004 Lappert, J. Chem. Soc., Dalton Trans. 1977,

2004

Go(TMPD)2 60-62 70/0.02 Lappert, J. Chem. Soc., Chem. Com. 13, 621 (1980)

Hf(NEt2)4 liquid 100/0.84 Bradley, J. Chem. Soc. A, 1969, 980 Hf(NEtMe)4 liquid 83/0.05 Becker & Gordon, 2000; Aldrich Hf(NMe2)4 30 70/0.73 Bradley, J. Chem. Soc. A, 1969, 980 Hg(N(SiMe3)2)2 liquid Earborn, J. Chem. Soc., Chem. Comm.,

1051 (1968) Ho(N(SiMe3)2)3 161-164 80-85/10’4 Bradley, J. Chem. Soc., Dalton 1973, 1021 In(N(SiMe3)2)3 168 Wannagat, J. Organomet. Chem. 33, 1

(1971) In(TMPD)3 Frey et al., Z. Anorg. Allg. Chem. 622,

1060 (1996) KN(SiHeXMe2)2 liquid Broomhall-Dillard, Mater. Res. Soc. 606,

139 (2000) KN(SiMe3)2 90-100/10’3 Fieser & Fieser 4, 407 La(N(SiMe3)2)3 145-149 100/10’4 Bradley, J. Chem. Soc., Dalton 1973, 1021 La(N‘BuSiMe3)3 146-147 90-95/10’4 Becker, Suh & Gordon, 2000 La(NiPr2)3 Aspinall, J. Chem. Soc., Dalton 1993, 993 La(TMPD)3 137-139 100/1074 Suh & Gordon, 2000 LiN(SiEtMe2)2 liquid 123/0.2 Broomhall-Dillard, Mater. Res. Soc. 606,

139 (2000) LiN(SiMe3)2 71-72 115/1 Inorg. Synth. 8, 19 (1966) Li(TMPD) Kopka, J. Org. Chem. 52, 448 (1987) Lu(N(SiMe3)2)3 167-170 75-80/10’4 Bradley, Chem. Comm. 1972, 349 Mg(N(SiMe32)2 123 Andersen, J. Chem. Soc., Dalton Trans. 1982,

887 Mg(rMPD)2 Eaton, JACS 111, 8016 (1989) Mn(N(SiBuMe2)2)2 liquid 143/0.06 Broomhall-Dillard & Gordon, 1999 Mn(N(SiMe3)2)2 55-60 112—120/0.2 Bradley, Trans. Met. Chem. 3, 253 (1978) Mn(N(SiMe3)2)3 108-110 PoWer, JACS 11, 8044 (1989) Mo(N‘BuSiMe3)3 Laplaza, Cummins, JACS 118, 8623

(1996) Mo2(NEt2)6 Chisholm, JACS 98, 4469 (1976) Mo,(NMo,)6 solid 100/1074 Chisholm, JACS 98, 4469 (1976) Mo(NEt2)4 liquid 80-110/10’4 Bradley & Chisholm, J. Chem. Soc. A

1971, 2741 Mo(NMe2)4 solid 40—70/0.1 Bradley & Chisholm, J. Chem. Soc. A

1971, 2741 NaN(Si“BuMe2)2 liquid 189/0.08 Broomhall-Dillard, Mater. Res. Soc. 606,

139 (2000) NaN(SiMe3)2 171-175 170/2 Chem. Ber. 94, 1540 (1961) Nh(N(SiMe3)2)3 solid Broomhall-Dillard & Gordon, 1998 Nh(NEt2)4 liquid Bradley & Thomas, Can. J. Chem. 40, 449

(1962) Nh(NEt2)5 >120 120/0.1 Bradley & Thomas, Can. J. Chem. 40, 449

(1962) Nh(NMe2)5 >100 100/0.1 Bradley & Thomas, Can. J. Chem. 40, 449

(1962) Nd(N(SiMe3)2)3 161-164 85-90/10’4 Bradley, J. Chem. Soc., Dalton 1973, 1021 Nd(NiPr2)3 Bradley,

Inorg. Nucl. Chem. Lett. 12, 735 (1976) Ni(N(SiMe3)2)2 liquid 80/0.2 Burger & Wannagat, Mh. Chem. 95, 1099

(1964) Ph(N(SiMe3)2)2 39 60/0.04 Lappert, J. Chem. Soc., Chem. Com. 16,

776 (1980) Ph(N1BuSiMe3)2 22 50/004 Lappert, J. Chem. Soc., Dalton Trans.

1977, 2004 Pr(N(SiMe3)2)3 155-158 88-90/10’4 Bradley, Chem. Comm. 1972, 349 sh(NMo,)3 liquid 50/0.5 CoWley, JACS 95, 6506 (1973) Sh(N(Me)(SiMe3))3 9-11 78—79/0.1 Birkofer & Ritter, Chem. Ber. 93, 424

(1960) Sc(N(SiMe3)2)3 172-174 Bradley, J. Chem. Soc., Dalton 1972, 1580 SiH2(NMe2)2 —104 93/760 Anderson et al., J. Chem. Soc. Dalton 12,

3061 (1987) SiH(NMe2)3 —90 62/45 Gelest, Pfaltz & Bauer, Strem Catalogs Si(NMe2)4 1-2 196/760 Gordon, Hoffman & RiaZ, Chem. Mater. 2,

480 (1990) Si(NHMe)4 37 45/005 Schmisbaur, Inorg. Chem. 37, 510 (1998)


US 6,969,539 B2 13 14

TABLE l-continued



Si(NHn-Pr)4 liquid 75/0.05 Schmisbaur, Inorg. Chem. 37, 510 (1998) Si(NEt2)4 3-4 74/19 Abel et al, J. Chem. Soc. 1965, 62;

Chemat Si(NCO)4 25-26 40/1 Forbes & Anderson, JACS 62, 761 (1940);

Gelest, Petrarch, ShoWa-Denko Si(NCO)4 25-26 40/1 Forbes & Anderson, JAGS 62, 761 (1940);

Gelest, Petrarch, ShoWa-Denko Sm(N(SiMe3)2)3 155-158 83-84/10’4 Bradley, Chem. Comm. 1972, 349 Sn(N(SiMe3)2)3 38 84/004 Chisholm, CVD 1, 49 (1995) Sn(NEt2)4 liquid 90/0.05 Jones & Lappert, J. Chem. Soc. 1965, 1944 Sn(NMe2)4 liquid 51/0.15 Jones & Lappert, J. Chem. Soc. 1965, 1944 Sn(N1Bu2)2 47 Lappert, J. Chem. Soc., Chem. Com. 13,

621 (1980) Sn(N‘Bu2)3 Hudson, J. Chem. Soc., Dalton Trans. 1976,

2369

Sn(N1BuSiMe3)2 19, liquid 50/0.04 Lappert, J. Chem. Soc., Dalton Trans. 1977, 2004

Sn(N‘BuSiMe3)3 Hudson, J. Chem. Soc., Dalton Trans. 1976, 2369

Sn(TMPD)2 Lappert, J. Chem. Soc., Chem. Com. 16, 776 (1980)

Sr(N(SiMe3)2)2 164 Westerhauser, Inorg. Chem. 30, 96 (1991) Ta(NEt2)4 120/0.1 Bradley & Thomas, Can. J. Chem. 40, 1355

(1962) Ta(NMe2)5 >180 100/0.1 Bradley & Thomas, Can. J.

Chem. 40, 1355 (1962); Strem Ta(N‘Bu)(NEt2)3 liquid 90/0.1 Inorgtech Ta(NEt)(NEt2)3 liquid 120/0.1 Becke-Goehring & Wunsch, Chem. Ber.

93, 326 (1960) Tb(N(SiMe3)2)3 162-165 78-82/10’4 Wolczanski, Inorg. Chem. 31, 1311 (1992) Th(NEt2)4 40-50/10’4 Reynolds & Edelstein, Inorg. Chem. 16,

2822 (1977) Th(NPr2)4 liquid 60-70/10’4 Reynolds & Edelstein, Inorg. Chem. 16,

2822 (1977) Ti(N(SiMe3)2)3 solid Bradley, J. Chem. Soc., Dalton 1972, 1580 Ti(NEt2)4 liquid 112/0.1 Bradley & Thomas, J. Chem. Soc. 1960,

3857 Ti(NiPr2)3 Kruse, Inorg. Chem. 9, 2615 (1970) Ti(NiPr2)4 82-85 110/0.001 Froneman, P, S, Si, Relat. Elem. 47, 273

(1990) Ti(NMe2)4 liquid 50/0.05 Bradley & Thomas, J. Chem. Soc. 1960,

3857 Tl(N(SiMe3)2)3 Allman, J. Organomet. Chem. 162, 283

(1978) U(N(SiMe3)2)3 137-140 80-100/10’3 Andersen, Inorg. Chem. 18, 1507 (1979) U(NEt2)4 115—1251.06 Jones, JACS 78, 4285 (1956) U(NPr2)4 liquid 40-50/10’4 Reynolds & Edelstein, Inorg. Chem. 16,

2822 (1977) V(N(SiMe3)2)3 >95 95/0.005 Bradley, J. Chem. Soc., Dalton 1972, 1580 V(NEt2)4 liquid 90/0.001 Bradley, Chem. Commun. 1964, 1064 V(NMe2)4 solid 50/0.001 Bradley, J. Chem. Soc. A, 1969, 2330 V(O)(NMe2)3 40 40/0.001 Davidson, Harris & Lappert, JCS Dalton

1976, 2268 W2(NEt2)6 solid 140-170/1074 Chisholm, JACS 97, 5626 (1975); 98, 4477

(1976) W2(NMeEt)6 solid 100-130/10’4 Burger & Wannagat, Monatsh. 95, 1099

(1964) W2(NMe2)6 solid 100-120/10’4 Burger & Wannagat, Monatsh. 95, 1099

(1964) W(N1Bu)2(NH‘Bu)2 89-90 60-65/10’4 Nugent & HarloW, Inorg. Chem. 19, 777

(1980) W(N1Bu)2(NEtMe)2 liquid 87/0.1 Suh & Gordon, 2000 W(N1Bu)2(NMe2)2 liquid 75/0.1 Suh & Gordon, 2000 Y(N(SiMe3)2)3 180-184 100/10’4 Bradley, J. Chem. Soc., Dalton 1973,

1021; Alfa Y(NiPr2)3 Bradley, Inorg. Nucl. Chem. Lett. 12,

735 (1976) Y(N‘BuSiMe3)3 158-160 90-95/1074 Suh & Gordon, 2000 Y(TMPD)3 177-179 100/1074 Suh & Gordon, 2000 Yb(N(SiMe3)2)3 162-165 Bradley, J. Chem. Soc., Dalton 1973, 1021 Yb(NiPr2)3 Bradley, Inorg. Nucl. Chem. Lett. 12, 735

(1976) Zn(N(SiMe3)2)2 liquid 120/0.1 Inorg. Chem. 23, 1972 (1984)

Schumann, Z. Anorg. Allg. Chem. 623,


US 6,969,539 B2 16

TABLE l-continued



1881 (1997) Zn(TMPD)2 Schumann, Z. Anorg. Allg. Chem. 623,

1881 (1997) Zr(NEt2)4 liquid 112/0.1 Bradley & Thomas, J. Chem. Soc. 1960,

3857 Zr(NEtMe)4 liquid 82/005 Becker & Gordon, 2000 Zr(NiPr2)4 >120 120/0.001 Bradley, Inorg. Nucl. Chem. Lett. 11, 155

(1975) Zr(NMe2)4 70 65—80/0.1 Bradley & Thomas, J. Chem. Soc. 1960,

3857

In Table 1, TMPD stands for 2,2,6,6-tetramethylpiperidide. Further examples may be found in the book Metal and

In at least some embodiments, metal alkyls are useful in

the practice of this invention. Some examples are given in Metalloid Amides, by M. F. Lappert, P. P. PoWer, A. R. 20 Sanger and R. C. Srivastava, published in 1980 by Ellis HorWood Ltd., a division of John Wiley & Sons.

Table 2, as Well as a commercial source or literature refer

ence of their synthesis.

TABLE 2

Some Volatile Organometallic Compounds

Melt. Pt. Vapor Press. Compound ° C. C./I‘orr Sources

AlMe3 15.4 20/8 Strem Ba(n-PrMe4CP)2 liquid Strem Ba(iPr4Cp)2 149-150 90/0.01 J. Am. Chem. Soc. 113, 4843-4851

(1991) Ba(Me5CP)2 265-268 140/0.01 J. Organomet. Chem. 325, 31-37 (1987) BeEt2 12, liquid 110/15 Strem BiMe3 liquid 110/760 Pfaltz & Bauer, Organometallics ca(‘Pr4Cp)2 196-200 190/0.01 J. Am. Chem. Soc. 113, 4843-4851

(1991) Ca(Me5CP)2 207-210 90/0.01 J. Organomet. Chem. 325, 31-37 (1987) CdMe2 —4.5 105.5/760 Strem CeCp3 452 230/001 Strem Ce(iPrCp)3 Strem Ce(Me4CP)3 solid Aldrich CoCp2 176-180 Aldrich, Strem CoCp(CO)2 liquid 37—38.5/2 Strem Co(CO)3NO liquid 50/760 Strem CrCp2 168-170 Aldrich, Strem Cr(Me5Cp)2 200 Strem Cr(iPrCp)2 solid Strem Cr(EtBZ)2 liquid 1 40-1 60/1 Strem CuCpPEt3 solid 60/0.01 Strem Er(Cp)3 285 200/0.01 Strem ErCPrCp)3 63-65 222/10 Aldrich, Alfa, Strem Er(BuCp)3 liquid 240/0.1 Aldrich, Alfa (pyrophoric) Eu(Me4CP)3 solid Aldrich FeCp(Me2NCH2Cp) liquid 91—92/0.5 Strem FeCp(‘BuCp) liquid 80/0.15 Strem GaMe3 —15, liquid 55.7/760 Strem GdCp3 295 Aldrich, Alfa, Strem Gd(‘PrCp)3 liquid 200/0.01 Erbil, U.S. Pat. NO. 4,882,206 (1989) InCp3 solid 50/0.01 Strem In(Me5Cp)3 Strem InMe3 88 Strem Ir(MeCp)(1,5-COD) Strem La(‘PrCp)3 liquid 180-195/0.01 Strem; Erbil, U.S. Pat. NO. 4,882,206

(1989) LaCp3 295 dec. 218/0.1 Aldrich, Alfa, Strem LaCp3(NCCH3)2 162 Inorganica Chim. Acta 100, 183-199

(1985) La(Me2NC2H4CP)3 75 160/0001 J. Organomet. Chem. 462, 163-174

(1993) Mg(PrCp)2 liquid Strem Mg(EtCP)2 liquid Aldrich, Strem MgCp2 180 160/0.1 Aldrich, Strem


US 6,969,539 B2 17

TABLE 2-continued

18

Some Volatile Organometallic Compounds

Melt. Pt. Vapor Press. Compound ° C. C./I‘orr Sources

MnCp2 175 Aldrich, Strem Mn(EtCp)2 liquid Aldrich (pyrophoric) Mn(Me5CP)2 292 Strem Mo(EtBZ)2 liquid Strem NdCp3 417 220/001 Aldrich, Alfa, Strem Nd(iPrCp)3 solid Aldrich, Alfa, Strem Ni(PF3)4 liquid 70.7/760 Strem PrCp3 427 220/001 Aldrich, Alfa, Strem Pr(iPrCp)3 50-54 Aldrich, Alfa, Strem SbEt3 156/760 Strem ScCp3 240 200/0.05 Aldrich, Strem SmCp3 356 220/001 Strem Sm(iPrCp)3 Zh. Neorg. Khim. 27, 2231-4 (1982) Sr(iPr4CP)2 151-153 Chem. Rev. 93, 1023-1-36 (1993) Sr(Me5CP)2 216-218 J. Organomet. Chem. 325, 31-37 (1987) Tb(iPrCp)3 solid Aldrich, Strem TmCp3 solid Strem Tm(iPrCp)3 MRS Symp. Proc. 301, 3-13 (1993) TlCp solid 75/0.1 Strem VCp2 165-167 200/0.1 Aldrich, Strem V(EtCp)2 liquid Aldrich W(iPrCp)2H2 liquid 122—125/0.1 Aldrich, Strem YCp3 296 200/2 Alfa, Strem Y(MeCp)3 Strem Y(“PrCp)3 Strem Y(BuCp)3 liquid Aldrich, Alfa, Strem YbCp3 277 150(vac.) Strem Yb(iPrCp)3 47 Zh. Neorg. Khim. 27, 2231-4 (1982) ZnEt2 —28, liquid 124/760 Aldrich, Strem ZnMe2 —42, liquid 46/760 Aldrich, Strem ZrCpZMe2 170 Aldrich, Strem Zr(‘BuCp)2Me2 Strem

In Table 2, Cp is an abbreviation for cyclopentadienide, MeSCp represents pentamethylcyclopentadienide, iPrCp represents isopropylcyclopentadienide, iPrMe4Cp stands for isopropyltetramethylcyclopentadienide, "Pr4Cp stands for tetraisopropylcyclopentadienide, EtCp stands for ethylcyclopentadienide, PrCp stands for propylcyclopentadienide, iPrCp stands for isopropylcyclopentadienide, BuCp stands for butylcyclopentadienide, BZ for benZenide, EtBZ for a mix ture of isomers of ethylbenZenide and 1,5-COD for 1,5 cyclooctadienide.

In at least some embodiments, metal or metalloid alkoX ides can be used in the practice of this invention. Suitable compounds are listed in Table 3, as Well as a commercial source or a literature reference of their synthesis.

TABLE 3

Some Volatile Metal or Metalloid AlkoXides

Vapor Melt. Pt. Press.

Compound ° C. O C./I‘orr Sources

Al2Et3(O—sec—Bu)3 liquid 190/0.1 Strem B(OMe)3 —29, liquid 68.7/760 Aldrich, Rohm

and Haas, Strem Hf(O‘Bu)4 liquid 90/5 Strem Nb(OEt)5 6, liquid 156/0.05 Aldrich, Chemat,

Strem

Ta(OEt)5 21 146/015 Aldrich, Chemat, Strem

Ti(OiPr)4 20 58/1 Aldrich, Chemat, DuPont, Strem

35

40

45

50

55

60

65

TABLE 3-continued

Some Volatile Metal or Metalloid AlkoXides

Vapor Melt. Pt. Press.

Compound ° C. O C./I‘orr Sources

Y(OCMe2CH2NMe2)3 liquid 80/0.001 Herrmann, Inorg. Chem. 36, 3545-3552(1997)

Zr(O‘Bu)4 liquid 81/3, 90/5 Aldrich, Strem

Metal halides may also be used in the practice of this invention, but they have the disadvantages that they tend to leave some halide impurity in the ?lm and cause corrosion of substrates or apparatus. 4. Reactions With Water and Alcohols.

In at least some embodiments, part of the silanol or phosphate is replaced With Water in order to deposit metal rich silicates and phosphates. In a CVD reactor, Water vapor tends to react very quickly With the vapors of the metal precursors near the vapor entrance to produce poWder, rather than ?lm on the substrate. In an ALD reactor such premature reactions are avoided because the reactants are introduced alternately into the reactor, so reactions near the entrance are prevented and reaction is con?ned to the surface of the substrate. However, Water tends to adsorb strongly on surfaces, so it can take a long time to purge the ALD reactor between pulses of the reactants.

Alcohols such as isopropanol and tert-butanol can alle viate these problems With Water, since the reactions of alcohols With metal compounds are sloWer, and the more volatile alcohols can be pumped more quickly from an ALD


US 6,969,539 B2 19

reactor. Alcohols such as isopropanol and tert-butanol are particularly appropriate for reactions involving thermally liable metal compounds. In some cases the substrate tem perature is raised in order to decompose alkyl alcohols and thereby remove their carbon content from the ?lm. A ther mally labile metal compound may self-decompose at higher substrate temperatures, so self-limiting ALD reactions can not be achieved.

The arene hydrates are a class of alcohols that decompose at loWer temperatures than ordinary alkyl alcohols, and thus can be used to provide carbon-free metal oxides at loW enough temperatures to avoid self-decomposition of even thermally labile metal compounds. For example, benZene hydrate decomposes easily to Water and benZene because of the aromatic stabiliZation of the benZene byproduct:

HO

O _> H2O +

Other examples of useful arene hydrates are alkyl substituted benZene hydrates such as the various isomers of toluene hydrate:

Other useful alcohols include the tWo naphthalene hydrates

“65 66 and alkyl-substituted naphthalene hydrates such as methyl naphthalene hydrate. Thus arene alcohols may be used in the reaction of metal compounds at moderate deposition con ditions. In particular, it can be used for the formation of metal oxides, or for the formation of metal silicates or metal phophates When used in combination With the silicon and phosphorus precursors described herein.

In at least some embodiments of the present invention, a metal oxide is obtained by reaction of a metal amide With Water. Suitable metal amides include any of those listed in Table 1. Thus, by Way of example, hafnium oxide Was prepared by ALD using Water vapor and tetrakis (dimethylamido)hafnium. This ALD reaction Was found to be surprisingly ef?cient, in that almost all of the precursor that Was delivered into the reaction chamber Was deposited as ?lm on the substrate and on the exposed Wall of the chamber. It Was also found to be surprisingly fast, going to completion (saturation of the surface reaction on a ?at surface) With less than 50 Langmuirs of vapor ?ux (1 Langmuir is the ?ux delivered to a surface in one second by

(13)

15

25

40

55

65

20 a partial pressure of 10'6 Torr of the precursor). The byproducts of the reaction Were found to consist of dim ethylamine vapor, Which does not etch the deposited hafnium oxide ?lm. Most surprisingly, the use of tetrakis (alkylamido)hafnium precursors succeeded in the ALD of highly uniform ?lms of hafnium oxide even in holes With very high aspect rations (over 40). By Way of contrast, the reactants commonly used in the prior art for ALD of hafnium oxide, HfCl4 and Hf(O-tert-Bu)4, have not succeeded in the uniform deposition of HfO2 in holes With such high aspect ratios. 5. VaporiZation of Reactants and Product Deposition.

Vapors of liquid precursors may be formed by conven tional methods, including heating in a bubbler, in a thin-?lm evaporator, or by nebuliZation into a carrier gas preheated to about 100 to 250° C. The nebuliZation may be carried out pneumatically or ultrasonically. Solid precursors may be dissolved in organic solvents, including hydrocarbons such as decane, dodecane, tetradecane, toluene, xylene and mesitylene, and With ethers, esters, ketones and chlorinated hydrocarbons. Solutions of liquid precursors generally have loWer viscosities than the pure liquids, so that in some cases it may be preferable to nebuliZe and evaporate solutions rather than the pure liquids. The liquids or solutions can also be evaporated With thin-?lm evaporators or by direct injec tion of the liquids into a heated Zone. Thin-?lm evaporators are made by Artisan Industries (Waltham, Mass.). Commer cial equipment for direct vaporiZation of liquids is made by MKS Instruments (Andover, Mass.), AT MI, Inc. (Danbury, Conn.), Novellus Systems, Inc. (San Jose, Calif.) and COVA Technologies (Colorado Springs, Colo.). Ultrasonic nebu liZers are made by Sonotek Corporation Milton, NY.) and Cetac Technologies (Omaha, Nebr.). The silicon precursors of the present invention may be

reacted With metal or metalloid amides, such as those in Table 1, to form metal or metalloid silicates. The silicon precursors of the present invention may be reacted With organometallic compounds, such as those in Table 2, to form metal silicates. The silicon precursors of the present inven tion may be reacted With metal or metalloid alkoxides, such as those in Table 3, to form metal or metalloid silicates. The silicon precursors of the present invention may also be reacted With other suitably reactive metal compounds to form metal silicates. For example, tris(tert-butoxy)silanol may be reacted With tris(tert-butyl(trimethylsilyl)amido) yttrium (Table 1) to form yttrium silicate (Examples 5 and 6). Also, tris(tert-butoxy)silanol may be reacted With tris (tert-butyl(trimethylsilyl)amido)lanthanum (Table 1) to form lanthanum silicate (Examples 7 and 8). Metal oxides may be obtained by reactin of a suitable metal and With Water. Tris(bis(trimethylsilyl)amido)lanthanum reacts With Water vapor to form a more lanthanum-rich silicate

(Example 21). Lanthanum oxide may be deposited from silicon-free precursors such as tris(2,2,6,6 tetramethylpiperidido)lanthanum (Example 22). The phosphorus precursors of the present invention may

be reacted With suitably reactive metal compounds, such as those in the Tables, to form metal phosphates. For example, diisopropylphosphate may be reacted With lithium bis (ethyldimethylsilyl)amide (Table 1) to provide a process for depositing lithium phosphate ?lms that are lithium ion conductors, as is shoWn in Examples 9 and 10. The process of the invention can be carried out in standard

equipment Well knoWn in the art of chemical vapor depo sition (CVD). The CVD apparatus brings the vapors of the reactants into contact With a heated substrate on Which the material deposits. A CVD process can operate at a variety of


US 6,969,539 B2 21

pressures, including in particular normal atmospheric pressure, and also loWer pressures. Commercial atmospheric pressure CVD furnaces are made in the USA by the Watkins Johnson Company (Scotts Valley, Calif), BTU International (North Billerica, Mass.) and SierraTherm (Watsonville, Calif). Commercial atmospheric pressure CVD equipment for coating glass on the ?oat production line is made in the USA by Pilkington North America (Toledo, Ohio), PPG Industries (Pittsburgh, Pa.) and AF G Industries (Kingsport, Tenn.). LoW-pressure CVD equipment is made by Applied Materials (Santa Clara, Calif), Spire Corporation (Bedford, Mass.), Materials Research Corporation (Gilbert, AriZ.), Novellus Systems, Inc. (San Jose, Calif), Genus (Sunneyvale, Calif), Mattson Technology (Frement, Calif), Emcoie Corporation (Somerset, N.J.), NZ Applied Tech nologies (Woburn, Mass.), COVA Technologies (Colorado Springs, Colo.) and CVC Corporation (Freemont, Calif). Apparatus adapted to atomic layer deposition (ALD) is available from Genus (Sunneyvale, Calif.) and ASM Micro chemistry (Espoo, Finland).

The process of the invention may also be carried out using atomic layer deposition ALD introduces a metered amount of a ?rst reactant component into a deposition chamber having a substrate therein for layer deposition. A thin layer of the ?rst reactant is deposited on the substrate. After a preselected time period, a metered amount of a second reactant component is then introduced into the deposition chamber, Which is deposited on and interacts With the already deposited layer of the ?rst reactant component. Alternating layers of ?rst and second reactant components are introduced into the deposition chamber and deposited on the substrate to form a layer of controlled composition and thickness. Alternation of deposition may be on the order of seconds to minutes and is selected to provide adequate time for the just introduced component to deposit on the substrate and for any excess vapor to be removed from the headspace above the substrate. It has been determined that the surface reactions are self-limiting so that a reproducible layer of predictable composition is deposited. Use of more than tWo reactant components is Within the scope of the invention.

In at least some embodiments of the invention, automo bile fuel injectors (Ford model CM-4722 F13Z-9F593-A) may be used to deliver pulses of the solutions of precursors into the nitrogen carrier gas. Solution is delivered each time a valve opens for about 50 milliseconds.

In another embodiment of the invention, 6-port sampling valves (Valco model EP4C6WEPH, Valco Instruments, Houston, Tex.) normally used for injecting samples into gas chromatographs may be used to deliver pulses of solutions into a suitable carrier gas. Each time that a valve is opened, solution ?oWs into a tube in Which solution is vaporiZed by heat from hot oil ?oWing over the outside of the tube. Carrier gas moves the vapor from the tube into the ALD reactor tube.

In at least some embodiments, a layer is deposited by ALD using an apparatus such as that illustrated in FIG. 1. According to at least some embodiments, measured doses of reactant vapor 30 are introduced into the heated deposition chamber 110 by the use of a pair of air-actuated diaphragm valves, 50 and 70 (Titan II model made by Parker-Hanni?n, Richmond Calif). The valves are connected by a chamber 60 having a measured volume V, and this assembly is placed inside an oven 80 held at a controlled temperature T2. The pressure of the reactant vapor 30 in the precursor reservoir 10 is equal to the equilibrium vapor pressure Peq of the solid or liquid reactant 20 at a temperature T1 determined by the surrounding oven 40. The temperature T1 is chosen to be

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22 high enough so that the precursor pressure Peq is higher than the pressure P dep in the deposition chamber. The temperature T2 is chosen to be higher than T1 so that only vapor and no condensed phase is present in the valves 50 and 70 or the chamber 60. In the case of a gaseous reactant, its pressure can be set by a pressure regulator (not shoWn) that reduces its pressure from the pressure in the precursor gas cylinder 10. A similar arrangement is provided for each reactive

precursor introduced into the deposition chamber 110. Thus, a precursor reservoir 11 holds a solid or liquid reactant 21 having a vapor pressure 31 at a temperature T1‘ maintained by surrounding oven 41. Valves 51 and 71 are connected by a chamber 61 having a measured volume V‘ and this assembly is housed in oven 81 at temperature T2‘.

Carrier gas (such as nitrogen) ?oWs at a controlled rate into inlet 90 in order to speed the How of the reactants into the deposition chamber and the purging of reaction byprod ucts and un-reacted reactant vapor. A static mixer may be placed in the tubing 100 leading into the reactor, to provide a more uniform concentration of the precursor vapor in the carrier gas as it enters the deposition chamber 110 heated by furnace 120 and containing one or more substrates 130. The reaction byproducts and un-reacted reactant vapors are removed by trap 140 before passing into a vacuum pump 150. Carrier gas exits from exhaust 160.

In operation, valve 70 is opened so that the pressure inside chamber 60 is reduced to a value Pdep close to that of the deposition chamber 110. Then valve 70 is closed and valve 50 is opened to admit precursor vapor from precursor reservoir 10 into chamber 60. Then valve 50 is closed so that the volume V of chamber 60 contains vapor of the precursor at a pressure Peq. Finally, valve 70 is opened to admit most of the precursor vapor contained in chamber 60 into the deposition chamber. The number of moles, n, of precursor delivered by this cycle can be estimated by assuming that the vapor obeys the ideal gas laW:

”=(P.Eq—PdEp)(V/RT 1) (14)

Where R is the gas constant. This expression also assumes that carrier gas from tube 90 does not enter chamber 60 through valve 70 during the brief time that it is open to release the precursor vapor. If mixing of carrier gas With the precursor vapor does occur during the time that valve 70 is open, then a larger dose of precursor vapor may be delivered, up to a maximum value

”=(P€q)(V/RT 1) (15)

if all the residual precursor vapor in chamber 60 is displaced by carrier gas. For precursors With relatively high vapor pressure (Peq>>Pdep), there is not much difference betWeen these tWo estimates of the precursor dose.

This cycle of delivering precursor 20 is repeated if necessary until the required dose of precursor 20 has been delivered into reaction chamber. Normally, in an ALD process, the dose of precursor 20 delivered by this cycle (or several such cycles repeated to give a larger dose) is chosen to be large enough to cause the surface reactions to go to completion (also called “saturation”).

Next a dose of vapor 31 from a second precursor 21 may be measured and delivered by a similar apparatus With components numbered similarly to the apparatus for the ?rst precursor 20.

In the case of precursors With vapor pressure so loW that Peq is less than Pdep, this method Will not deliver any precursor vapor into the deposition chamber. The vapor


US 6,969,539 B2 23

pressure can be increased by raising the temperature T1, but in some cases a higher temperature Would result in thermal decomposition of the precursor. In such cases of thermally sensitive precursors With loW vapor pressure, vapor may be delivered using the apparatus in FIG. 2. The chamber 220 is ?rst pressuriZed With carrier gas delivered through tube 240 and valve 200 from a pressure controller (not shoWn). Valve 200 is then closed and valve 210 opened to alloW the carrier gas to pressuriZe precursor reservoir 220 to pressure PM. The mole fraction of precursor vapor in the vapor space 30 of reservoir 10 is then Peq/Pm. If PM is set to a pressure larger than the pressure P dep in the deposition chamber, then the number of moles delivered in a dose can be estimated from the equation

Where V is the volume of the vapor space 30 in chamber 10. This dose is delivered by opening valve 230. If carrier gas from tube 90 enters the volume 30 during the time that the valve 230 is open, then a dose someWhat larger than this estimate may be delivered. By making the volume V large enough, a precursor dose that is certainly large enough to saturate the surface reaction may be delivered. If the vapor pressure Peq is so loW that the required volume V Would be impracticably large, then additional doses from volume V may be delivered before delivering a dose of the other reactant. A similar apparatus is provided for each precursor reac

tant of the system. Thus, chamber 221 is ?rst pressuriZed With carrier gas delivered through tube 241 and valve 201 from a pressure controller (not shoWn). Valve 201 is then closed and valve 211 is opened to alloW the carrier gas to pressuriZe precursor reservoir 11 to pressure PM. This dose is delivered by opening valve 231. Carrier gas from tube 91 promotes transport of the metered dose to the deposition chamber.

In an isothermal deposition Zone, material is generally deposited on all surfaces exposed to the precursor vapors, including substrates and the interior chamber Walls. Thus it is appropriate to report the precursor doses used in terms of moles per unit area of the substrates and exposed chamber Walls.

The liquids and solutions described herein may also be used as metal-containing precursors for other types of depo sition processes, such as spray coating, spin coating or sol-gel formation of mixed metal oxides. The high solubility and miscibility of these precursors is an advantage in forming the required solutions.

The amides disclosed in these examples appeared to be non-pyrophoric by the methods published by the United States Department of Transportation. One test calls for placing about 5 milliliters of the material on an non ?ammable porous solid, and observing that no spontaneous combustion occurs. Another test involves dropping 0.5 mil liliters of the liquid or solution on a Whatman No. 3 ?lter paper, and observing that no ?ame or charring of the paper occurs.

The precursors generally react With moisture in the ambi ent air, and should be stored under an inert, dry atmosphere such as pure nitrogen gas.

The invention may be understood With reference to the folloWing examples Which are for the purpose of illustration only and Which are not limiting of the invention, the full scope of Which is set forth in the claims Which folloW.

EXAMPLE 1

CVD of Zirconium Silicate

A solution (1% by Weight) of tris(tert-butoxy)silanol in mesitylene Was pumped at a rate of 6 ml/hour into a 1/16“

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24 OD. tee joint through Which nitrogen gas ?oWed at 0.4 L/min. The resulting fog ?oWed into a tube heated to 250° C. A solution (1% by Weight) of tetrakis(ethylmethylamido) Zirconium in mesitylene Was pumped at a rate of 12 ml/hour into another tee joint through Which nitrogen gas ?oWed at 0.4 L/min. The resulting fog ?oWed into the same heated tube. The gas pressure Was maintained at 5 Torr by a vacuum pump attached to the outlet of the glass tube by a liquid nitrogen trap. Substrates of silicon and glassy carbon placed inside the tube Were coated With a ?lm of Zirconium silicate Whose thickness varied along the length of the tube. Analysis of the ?lm by Rutherford backscattering spectroscopy gave a composition ZrSi2O6 for ?lms deposited on glassy carbon. No carbon or nitrogen Was detected in the ?lm. The refrac tive indexes of ?lms deposited on silicon Were found to be about 1.6 by ellipsometry.

EXAMPLE 2

ALD of Zirconium Silicate

Example 1 Was repeated except that the precursors Were injected in alternate pulses spaced 5 seconds apart, instead of continuously. A?lm of similar composition, ZrSi2O6, Was deposited With uniform thickness along the Whole length of the heated Zone. The thickness Was about 0.3 nm per cycle.

EXAMPLE 3

CVD of Hafnium Silicate

Example 1 Was repeated With tetrakis(ethylmethylamido) hafnium in place of tetrakis(ethylmethylamido)Zirconium. Films of composition approximately HfSi2O6 Were formed. No carbon or nitrogen Was detected in the ?lm. The refrac tive indexes of ?lms deposited on silicon Were found to be about 1.6 by ellipsometry.

EXAMPLE 4

ALD of Hafnium Silicate

Example 3 Was repeated except that the precursors Were injected in alternate pulses spaced 5 seconds apart, instead of continuously. A?lm of similar composition, HfSi2O6, Was deposited With uniform thickness along the Whole length of the heated Zone. The thickness Was about 0.3 nm per cycle.

EXAMPLE 5

CVD of Yttrium Silicate

Example 1 Was repeated With tris(tert-butyl (trimethylsilyl)amido)yttrium in place of tetrakis (ethylmethylamido)Zirconium. Films of composition approximately Y2Si2O7 Were formed. No carbon or nitrogen Was detected in the ?lm. The refractive indexes of ?lms deposited on silicon Were found to be about 1.6 by ellip sometry.

EXAMPLE 6

ALD of Yttrium Silicate

Example 5 Was repeated except that the precursors Were injected in alternate pulses spaced 5 seconds apart, instead of continuously. A ?lm of similar composition, Y2Si2O7, Was deposited With uniform thickness along the Whole length of the heated Zone. The thickness Was about 0.3 nm per cycle. Composition approximately Y2Si2O7.


US 6,969,539 B2 25

EXAMPLE 7

CVD of Lanthanum Silicate

Example 1 Was repeated With tris(bis(trimethylsilyl) amido)lanthanum in place of tetrakis(ethylmethylamido) Zirconium and tetradecane in place of mesitylene. Films With a La:Si ratio of about 0.9 Were formed on a glassy carbon substrate at a substrate temperature of 250° C. No carbon or nitrogen Was detected in the ?lms.

EXAMPLE 8

ALD of Lanthanum Silicate

Example 7 Was repeated except that the precursors Were injected in alternate pulses spaced 5 seconds apart, instead of continuously. A?lm of similar composition Was deposited With uniform thickness along the Whole length of the heated Zone.

EXAMPLE 9

CVD of Lithium Phosphate

Liquid lithium bis(ethyldimethylsilyl)amide (1 part by Weight) Was mixed With mesitylene (99 parts). The resulting solution Was nebuliZed by pumping at a rate of 12 ml/hour into a tee joint into nitrogen gas ?oWing at 0.30 L/min into the deposition Zone inside a tube (24 mm inside diameter) in a furnace heated to 250° C. Simultaneously a 1% mesitylene solution of diisopropylphosphate Was similarly nebuliZed into another nitrogen carrier gas stream ?oWing at 0.30 L/min into the same tube furnace. The gas pressure Was maintained at 5 Torr by a vacuum pump attached to the outlet of the glass tube by a liquid nitrogen trap. A thin ?lm Was deposited on a silicon substrate placed on the bottom of the glass tube, as Well as on the inside of the tube. The thickness pro?le shoWed a peak near the gas entrance to the tube furnace. The ?lm Was analyZed by X-ray photoelectron spectroscopy to contain lithium, phosphorus and oxygen.

EXAMPLE 10

ALD of Lithium Phosphate

Example 9 Was repeated With the change that the mate rials Were introduced in alternating pulses spaced 5 seconds apart in time. A similar lithium phosphate ?lm Was deposited, except that the thickness Was nearly constant throughout the deposition Zone.

COMPARATIVE EXAMPLE 1

Control Deposition With Only tris(tert-butoxy) silanol

Example 1 Was repeated using only the silicon precursor and no Zirconium precursor. No ?lm Was deposited.


Control Deposition With Only tetrakis (ethylmethylamido)Zirconium

Example 1 Was repeated using only the Zirconium pre cursor and no silicon precursor. No ?lm Was deposited.


Control Deposition With Only tetrakis (ethylmethylamido)hafnium

Example 3 Was repeated using only the hafnium precursor and no silicon precursor. No ?lm Was deposited.

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26 COMPARATIVE EXAMPLE 4

Control Deposition With Only tris(tert-butyl (trimethylsilyl)amido)yttrium

Example 5 Was repeated using only the yttrium precursor and no silicon precursor. No ?lm Was deposited.


Control Deposition With Only tris(bis (trimethylsilyl)amido)lanthanum

Example 7 Was repeated using only the lanthanum pre cursor and no silicon precursor. No ?lm Was deposited.


Control Deposition With Only Diisopropylphosphate

Example 9 Was repeated using only the phosphorus pre cursor and no lithium precursor. No ?lm Was deposited.


Control Deposition With Only Lithium bis (ethyldimethylsilyl)amide

Example 9 Was repeated using only the lithium precursor and no phosphorus precursor. No ?lm Was deposited.

EXAMPLE 11

ADL Formation of Metal Silicates and Phosphates

The ALD examples 2, 4, 6, 8 and 10 Were repeated using automobile fuel injectors (Ford model CM-4722 F13Z 9F593-A) to deliver pulses of the solutions of precursors into the nitrogen carrier gas. About 0.05 m of solution Was delivered each time that a valve Was opened for about 50 milliseconds. Similar results Were obtained.

The ALD examples 2, 4, 6, 8 and 10 Were repeated using a 6-port sampling valves (Valco model EP4C6WEPH, Valco Instruments, Houston, Tex.) normally used for injecting samples into gas chromatographs to deliver pulses of tet radecane solutions into the nitrogen carrier gas. External sample loops having volumes of 50 microliters Were used. Each time that a valve Was opened, about 50 microliters of solution ?oWed into a 1/16“ OD, 0.040“ I.D. nickel tube in Which the solution Was vaporiZed by heat from hot oil ?oWing over the outside of the tube. Nitrogen carrier gas moved the vapor from the small tube into the ALD reactor tube. Similar results Were obtained.

In another series of examples, pulses of those precursors that are liquids at room temperature Were delivered for ALD experiments similar to examples 2, 4, 6, 8 and 10 using 4-port sampling valves With small (0.5 microliter) internal sampling loops (Valco model EH2CI4WE.5PH, Valco Instruments, Houston, Tex.). Each time that a valve Was opened, about 0.5 microliters of liquid ?oWed into a 1/16“ OD, 0.040“ I.D. nickel tube in Which the liquid Was vaporiZed by heat from hot oil ?oWing over the outside of the tube. Nitrogen carrier gas moved the vapor from the small tube into the ALD reactor tube. Similar results Were obtained.

EXAMPLE 12

ALD of Hafnium Oxide

A hafnium oxide layer Was deposited using the apparatus of FIG. 1. Doses of 05x10“9 moles/cm2 of tetrakis


US 6,969,539 B2 27

(dimethylamido)hafnium vapor and 4><10_9 moles/cm2 of Water vapor Were injected alternately every 5 seconds into a deposition chamber held at 250° C. The chamber Was also fed a continuous How of nitrogen carrier gas suf?cient to maintain a pressure of 0.15 Torr. The deposition chamber had a cross-sectional area of 2.3 square centimeters in the plane perpendicular to the direction of gas ?oW through the chamber. The outlet of the deposition chamber Was attached to a vacuum pump With capacity (195 liters/minute) suf? cient to pump a volume equal to the deposition chamber in about 0.012 seconds. As a result of these reaction conditions, a transparent,

electrically insulating hafnium oxide ?lm Was deposited on substrates in the deposition chamber and onto its inner Walls. Its composition Was determined to be HfO2 by Rutherford backscattering spectroscopy (RBS) of a ?lm on a glassy carbon substrate. No carbon or nitrogen Was detected (<1 atomic percent). By ellipsometry, its thickness Was deter mined to be 0.1 nanometer/cycle and its refractive index 2.05. Combining data from RBS and ellipsometry yielded a density of about 9. The thickness Was constant over the Whole deposition region, to Within the estimated measure ment error of about 1%. Small-angle X-ray re?ectivity measurements con?rmed the thickness and gave a density of 9.23 g/cm3. X-ray re?ectivity also shoWed that the ?lms are very smooth, With root mean square surface roughness about 0.4 nm for a ?lm 43 nm thick. Scanning electron microscopy shoWed that ?lms groWn at 150° C. are even smoother than the ones groWn at 250° C.

Repeating Example 12 With higher doses of either reac tant did not increase the ?lm thickness or change its prop erties. These results shoW that the surface reactions are self-limiting. This conclusion Was con?rmed by placing inside the deposition chamber 110 a quartZ crystal micro balance (not shoWn), Which shoWed that the amount of mass deposited ?rst increased and then reached a plateau as the siZe of each dose Was increased. As a result of these self-limiting surface reactions, uniform ?lms could be deposited inside holes With ratios of length to diameter over 50. Uniformity of thickness inside these holes Was improved by increasing the dose to 10 times the minimum required for saturation of the reactions on a ?at surface Without the holes. Reducing the capacity (speed) of the vacuum pump also helps to improve the step coverage by reducing the linear velocity of the vapors through the deposition chamber, thereby increasing the time during Which the vapors can diffuse doWn the holes, i.e. increasing the ?ux (Langmuirs of exposure). FIG. 3 shoWs a scanning micrograph of holes coated With hafnium oxide, cleaved to reveal their highly uniform thickness. The hafnium oxide layer is the bright line outlining each of the narroW vertical holes in the silicon, Which appears as a dark background. At the top of the micrograph is the upper surface of the silicon from Which the holes Were etched prior to the deposition of the hafnium oxide.

Repeating Example 12 With substrate temperatures in the range from 1000 C. to 300° C. gave similar results. At temperatures above 300° C., the thickness increased With increasing the dose of tetrakis(dimethylamido)hafnium. This shoWs that the surface reaction is not self-limiting at tem peratures above 300° C., due to thermal decomposition of tetrakis(dimethylamido)hafnium.

EXAMPLE 13

ALD of Zirconium Oxide

Example 12 Was repeated With tetrakis(dimethylamido) Zirconium in place of tetrakis(dimethylamido)hafnium. Films of Zirconium dioxide With similar properties Were deposited.

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28 EXAMPLE 14


Example 12 Was repeated With tert-butanol vapor in place of Water vapor. Films of hafnium dioxide With similar properties Were deposited.

EXAMPLE 15

ALD of Tantalum Oxide

Example 12 Was repeated With ethylimidotris (diethylamido)tantalum vapor in place of tetrakis (dimethylamido)hafnium vapor. Transparent ?lms of Ta2O5 Were deposited. They have a refractive index of 2.2, and a thickness of about 0.06 nm per cycle.

EXAMPLE 16

ALD of Aluminum Phosphate

ALD Was carried out using alternating doses of 3x10“9 moles/cm2 of the vapors of trimethylaluminum and diiso propylphosphate at a substrate temperature of 400° C. Trans parent aluminum phosphate ?lms With approximate compo sition Al2P4O13 Were deposited at a rate of 0.1 nm per cycle. They had a refractive index of about 1.5.

EXAMPLE 17

ALD of Aluminum Silicate

ALD Was carried out using alternating doses of 3x10“9 moles/cm2 of trimethylaluminum vapor and 12x10“8 moles/cm2 of tris(tert-butoxy)silanol vapor at a substrate temperature of 300° C. Transparent aluminum silicate ?lms With approximate composition Al2Si8O19 Were deposited at a remarkably high rate of 1 nm per cycle. They had a refractive index of about 1.48. The surfaces of the ?lms are very smooth; atomic force microscopy determined a root mean square roughness of less than 0.8 nm for an aluminum silicate ?lm 150 nm thick. The tensile stress in a ?lm 2 micrometers thick on a silica substrate Was measured to be about 0.2 giga-Pascals. A similar ?lm deposited on single crystalline silicon shoWed a smaller tensile stress of 0.03 giga-Pascals. A ?lm 6 microns thick shoWed cracks and delamination because of the tensile stress.

This tensile stress can be reduced, eliminated, or even reversed to compressive stress by plasma treatment. The deposition is temporarily halted after a thin layer (such as 5 to 10 nm) has been deposited, a radio-frequency plasma (in a loW-pressure gas such as O2+argon) is applied, and then the plasma poWer is stopped and the deposition is resumed. Multiple cycles of deposition and plasma treatment may be used to build up thicker layers With tensile or compressive stress values adjusted to the requirements of particular applications, particularly those requiring thicker ?lms.

EXAMPLE 18


ALD Was carried out using alternating doses of 3x10-9 moles/cm2 of trimethylaluminum vapor and 3><10_8 moles/ cm2 of tris(tert-butoxy)silanol vapor at a substrate tempera ture 200° C. Transparent aluminum silicate ?lms With approximate composition Al2Si16O35 Were deposited at a remarkably high rate of 2 nm per cycle. They had a refrac tive index of about 1.47.


US 6,969,539 B2 29

EXAMPLE 19


ALD Was carried out With alternating doses of 3x10-9 moles/cm2 of tris(dimethylamino)aluminum vapor and 3x10‘8 moles/cm2 of tris(tert-butoxy)silanol vapor at a substrate temperature 250° C. An aluminum silicate ?lm Was formed With thickness 0.1 nm/cycle and a refractive index of about 1.46.

EXAMPLE 20


Example 19 Was repeated With tris(tert-pentyloxy)silanol vapor in place of the tris(tert-butoxy)silanol vapor. Similar results Were obtained

EXAMPLE 21


Example 19 Was repeated With a dose of Water vapor betWeen the doses of tris(dimethylamino)aluminum vapor and tris(tert-butoxy)silanol vapor. A similar ?lm Was obtained With very uniform thickness of 0.1 nm/cycle (11%) along the direction of gas ?oW.

EXAMPLE 22


Example 12 Was repeated With tris(bis(trimethylsilyl) amido)lanthanum vapor in place of tetrakis(dimethylamido) hafnium vapor and With the apparatus of FIG. 2, used as described herein above. Transparent oxide ?lms With a La:Si ratio of about 2 Were formed on substrates at a substrate temperature of 250° C. No carbon or nitrogen Was detected in the ?lms. They have a refractive index of 1.7, and a thickness of about 0.1 nm per cycle.

EXAMPLE 23

ALD of Lanthanum Oxide

ALD can be carried out With alternating doses of tris(2, 2,6,6-tetramethylpiperidido)lanthanum vapor using the apparatus of FIG. 2 and Water vapor to form lanthanum oxide ?lms.

EXAMPLE 24

ALD of Silicon Dioxide

ALD can be carried out With alternating doses of tetrai socyanatosilane vapor and tris(tert-butoxy)silanol vapor to form silicon dioxide ?lms. Larger ?uxes of exposure (>10'7 Langmuirs) are required for these less reactive precursors.

Those skilled in the art Will recogniZe or be able to ascertain using no more than routine experimentation, many equivalents to the speci?c embodiments of the invention described speci?cally herein. Such equivalents are intended to be encompassed in the scope of the folloWing claims. What is claimed is: 1. A process for forming materials comprising silicon,

oxygen and one or more metals or metalloids, comprising:

reacting the vapor of one of an alkoxysilanol and an alkoxysilanediol together With a vapor of one or more of a metal compound and a metalloid compound.

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30 2. A process for forming materials comprising silicon,

oxygen and one or more metals or metalloids, comprising: exposing a substrate alternately to the vapor of one or an

alkoxysilanol and an alkoxysilanediol and the vapor of one or more of a metal compound or a metalloid compound to form a ?lm on the substrate.

3. The process of claim 1, Wherein compound is deposited as a ?lm on a substrate.

4. The process as in claim 1 or 2, Wherein the silanol has the formula

R6 o

Where the R” represents hydrogen, alkyl groups, ?uoro alkyl groups or alkyl groups substituted by other atoms or groups, R” being any one of the groups R1 through R9, and Where R” are the same or different.

5. The process of claim 4, Wherein the groups R” contain betWeen one and four carbons and are the same or different.

6. The process of claim 5, Wherein the groups R” are all methyl groups.

7. The process of claim 5, Wherein R1, R4 and R7 are ethyl groups and R2, R3, R5, R6, R8 and R9 are methyl groups and the silanol has the formula

CH3— CH3

CH3— CH3

8. The process of claim 1 or 2, Wherein a metal or metalloid compound contains metal-nitrogen or metalloid nitrogen bonds.

9. The process of claim 8, Wherein a metal or metalloid compound is selected from Table 1.

10. The process of claim 1 or 2, Wherein a metal com pound is selected from Table 2.

11. The process of claim 1 or 2, Wherein a metal or metalloid compound is selected from Table 3.

12. A process for forming materials comprising phosphorus, oxygen and one or more metals or metalloids, comprising:

reacting a vapor of a bis(alkyl)phosphate With a vapor of one or more of a metal compound and a metalloid compound.

13. A process for forming materials comprising phosphorus, oxygen and one or more metals or metalloids, comprising:

exposing a substrate alternately to a vapor of a bis(alkyl) phosphate and a vapor of one or more of a metal compound and metalloid compound to form a ?lm on the substrate.


EXHIBIT B


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(12) Ulllted States Patent (10) Patent N0.: US 8,334,016 B2 Gordon et al. (45) Date of Patent: Dec. 18, 2012

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SILICATES AND PHOSPHATES’ AND 6,969,539 B2 * 11/2005 Gordon et al. ......... .. 427/255.29 SILICON DIOXIDE 7,064,227 B1 6/2006 Lei et al.

7,097,878 B1 8/2006 Rulkens et al. (75) Inventors: Roy G. Gordon, Cambridge, MA (US); 7,109,129 B1 9/2006 Papasouliotis

Jill s_ Becker, Cambridge, MA (Us); 7,115,528 B2 * 10/2006 Vaartstra et al. ............ .. 438/758 - 7,129,189 B1 10/2006 Hausmann et al.

Dem?“ Ilaflsmann’ L05 Gatos’ CA 7,135,418 B1 11/2006 Papasouliotis (Us), 561%‘ s‘lhs Cary’ NC (Us) 7,148,155 B1 12/2006 Tarafdar etal.

7,157,385 B2 1/2007 Derderian et a1. (73) Assignee: President and Fellows of Harvard 7,163,899 B1 1/2007 Cho et al.

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2003/0015764 A1 1/2003 Raajimakers et al. (21) App1_ NO; 12/407556 2003/0129087 A1 7/2003 Barbee et al.

2004/0018694 A1 1/2004 Lee et al. ' . 2005/0065358 A1 3/2005 Itsuki et al.

(22) Wed‘ Mar‘ 19’ 2009 2006/0046426 A1 3/2006 Sandhu et al. _ _ _ 2006/0046518 A1 3/2006 Hill et al.

(65) Prlor Publlcatloll Data 2006/0062910 A1 3/2006 Meiere 2006/0110936 A1 5/2006 Hill et al.

Us 2012/0028478A1 Feb- 2’ 2012 2006/0246719 A1 11/2006 Rueger etal. 2006/0258078 A1* 11/2006 Lee et al. .................... .. 438/216

Related US. Application Data 2007/0160761 A1 7/2007 Reuter et a1.

(63) Continuation of application No. 11/ 199,032, ?led on FOREIGN PATENT DOCUMENTS

cont1nuat1on of appl1cat1on No. 10/381,628, ?led as EP 0 560 617 A 9/1993 application No. PCT/US0l/30507 on Sep. 28, 2001, EP 1067595 A2 1/2001 noW Pat. No. 6,969,539. JP 3177560 A 8/1991

JP 04359515 12/1992 (60) Provisional application No. 60/236,283, ?led on Sep. JP 06140390 A 5/ 1994

28, 2000, provisional application No. 60/253,917, JP 07153696 A 6/1995 ?led on NOV 29 2000 JP 2001-074931 A 3/2001

' ’ ' JP 2002-093803 A2 3/2002

(51) I t Cl JP 2002-093804 A2 3/2002 n . . .

C23C 16/40 (2006.01) (Commued)

(52) US. Cl. .............. .. 427/255.31; 427/255.36; 117//84; OTHER PUBLICATIONS 117 88

(58) Field of Classi?cation Search 427/255 31 Aarik, J., et al., “In?uence of substrate temperature on atomic layer 117/84' 88’ growth and properties of HfO2 thin ?lms”. Thin Solid Films 340

See application ?le for complete search history. (1999) 1104 16* Continued

(56) References Cited ( )

U.S. PATENT DOCUMENTS

4,386,117 A 5/1983 Gordon 4,474,642 A 10/1984 Nakane et a1. 4,512,862 A 4/1985 Rigby 4,723,978 A 2/1988 Clodgo et a1. 4,792,463 A 12/1988 Okadaet a1. 4,956,323 A * 9/1990 Hefner ........................ .. 502/113

5,064,686 A 11/1991 McGeary 5,389,401 A 2/1995 Gordon 5,403,630 A 4/1995 Matsuiet a1. 5,710,075 A 1/1998 Tseng 5,922,787 A 7/1999 Kondo et a1. 6,090,442 A 7/2000 Klaus et a1. 6,159,855 A * 12/2000 Vaartstra ..................... .. 438/681

6,203,613 B1 3/2001 Gates etal. 6,258,707 B1 7/2001 UZoh 6,335,288 B1 1/2002 Kwan et a1. 6,339,004 B1 1/2002 Kim 6,342,432 B1 1/2002 Wang 6,359,160 B1 3/2002 Sun etal. 6,395,209 B2 5/2002 Yoshida et a1. 6,482,733 B2 11/2002 Raaijmakers et a1. 6,534,395 B2 3/2003 Werkhoven et al.

Primary Examiner * Bret Chen

(74) Attorney, Agent, or Firm *Wilmer Cutler Pickering Hale and Dorr LLP

(57) ABSTRACT

Metal silicates or phosphates are deposited on a heated sub strate by the reaction of vapors of alkoxysilanols or alky lphosphates along With reactive metal amides, alkyls or alkoxides. For example, vapors of tris(tert-butoxy)silanol react With vapors of tetrakis(ethylmethylamido)hafnium to deposit hafnium silicate on surfaces heated to 3000 C. The product ?lm has a very uniform stoichiometry throughout the reactor. Similarly, vapors of diisopropylphosphate react With vapors of lithium bis(ethyldimethylsilyl)amide to deposit lithium phosphate ?lms on substrates heated to 250° C. Sup plying the vapors in alternating pulses produces these same compositions With a very uniform distribution of thickness and excellent step coverage.

10 Claims, 3 Drawing Sheets


US 8,334,016 B2 Page 2

FOREIGN PATENT DOCUMENTS

JP 3409290 5/2003 KP 10-2005-0039421 4/2005 KR 156980 A2 7/1998 WO WO-91/08322 A1 6/1991 WO WO-97/38355 10/1997 WO WO-98/15669 A 4/1998 WO WO-99/29924 A 6/1999 WO WO-99/29926 A 6/1999 WO WO-00/16377 A2 3/2000 WO WO-01/27347 4/2001 WO WO-01/45156 A1 6/2001 WO WO-02/27063 A2 4/2002 WO WO-03/083167 10/2003

OTHER PUBLICATIONS

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Solid Films, ElsevieriSequoia S.A., Lausanne, Ch, vol. 365, No. 2, pp. 251-263, XP004197205, ISSN: 0040-6090, Apr. 2000. European Search Report issued for European Patent Application No. EP 06026277, dated Feb. 27, 2007, 2 pages. Ferguson et al., “Atomic Layer Deposition of A1 203 and SiO2 on BN Particles using Sequential Surface Reactions”, Applied Surface Sci ence, vols. 162-163, pp. 280-292, 2000. Ferguson et al., “Atomic Layer Deposition of SiO2 Films on BN Particles using Sequential Surface Reactions”, Chem. Mater, vol. 12, pp. 3472-3480, 2000. Fix, R. et al., “Chemical Vapor Deposition of Titanium, Zirconium, and Hafnium Nitride Thin Films,” Chemistry of Materials 3 Nov./ Dec. 1991, No. 6, Washington, DC, US, pp. 1138-1148. Furumura, Y. Abstract for “High-K dielectrics for DRAM applica tions” (1996), 1 Page. Gasser et al., “Quasi-Monolayer Deposition of Silicon Dioxide”, Thin SolidFilms, vol. 250, pp. 213-218, 1994. George et al., “Atomic Layer Controlled Deposition of SiO2 and Al203 Using ABAB . . . binary reaction sequence chemistry”, Appl.

Surf Sci., 82/83, pp. 460-467, 1994. gordon et al., “Vapor Deposition of Metal Oxides and Silicates: Possible Gate Insulators for Future Microelectronics,” Chem. Mater., 2001, 13, pp. 2463-2464. Haukka, et al., “Chemisorption of chromium acetylacetonate on porous high surface area silica,” Applied Surface Science 75, 1994, 220-227, 8 pages. Hausmann et al., “Rapid Vapor Deposition of Highly Conformal Silica Nanolaminates”, Science, vol. 298, pp. 402-406, 2002. Hausmann et al. “Atomic Layer Deposition of Hafnium and Zirco nium Oxides Using Metal Amide Precursors” Chem. Mater 2002, 14, 4350-4358. Hughes et al. “Why are some properties more dif?cult to predict than others? A study of QSPR models of solubility, melting point, and Log P” J'. Chem. Int. Model, 2008,48, 220-232. Ikeda, Y. et al., OZone/Organic-Source APCVD for ULSI Re?ow Glass Films; NE CResearch and Development, Nippon Electric, Ltd., No. 94, pp. 1-7, XP000067542, ISSN: 0547-051X, Jul. 1, 1989. International Search Report of the International Searching Authority, the European Patent Of?ce, for International Application No. PCT/ US03/09736, mailing date Sep. 12, 2003, 7 pages, 3 pages. International Search Report of the International Searching Authority, the European Patent Of?ce, for PCT/US01/30507, mailing date Aug. 19, 2002, 5 pages. Jeon et al. “Thermal stability of ultrathin ZrO2 ?lms prepared by chemical vapor deposition on Si(100)” Applied Physics Letters, vol. 78, No. 3, Jan. 15,2001 (368-370). Jones, et al., “MOCVD and ALD of High-K Dielectric Oxides Using Alkoxide Precursors,” Chemical Vapor Deposition, 2006, 12, pp. 83-98. Kang et al. Abstract for “Electrical characteristics of highly reliable ultrathin hafnium oxide gate dielectric” (2000), 1 Page. Kang et al. Abstract for “Highly reliable thin hafnium oxide gate dielectric” (2000), 1 Page. Kingon et al., “Alternative dielectrics to silicon dioxide for memory and logic devices”, Nature, vol. 406, pp. 1032-1038, 2000. Klaus et al., “Atomic Layer Deposition of SiO2 at Room Temperature using NH3 -catalyZed Sequential Surface Reactions”, Surf Sci., vol. 447, pp. 81-90, 2000. Klaus et al., “Atomic Layer Deposition of SiO2 using Catalyzed and UncatalyZed Self-Limiting Surface Reactions”, Surface Review and Letters, vol. 6, No. 3, pp. 435-448, 1999. Lee et al. Abstract for “High-quality ultrathin CVD HfO2 gate stack with poly-Si gate electrode” (2000), 1 Page. Lee et al. Abstract for “Ultrathin hafnium oxide with low leakage and excellent reliability for alternative gate dielectric application,” Tech nical Digest: International Electron Devices Meeting, 1999, 1 Page. Lee et al ., “Mass Production Worthy HfOZiAlZO3 Laminate Capaci tor Technology Using Hf Liquid Precursor for Sub-100nm DRAMS”, Presented at IEEE IEDM (International Electronic Devices Meeting), San Francisco, CA, Dec. 9-11, 2002, 4 pages. Leng et al. Abstract for “Rotating compensator spectroscopic ellipsometry (RCSE) and its application to high-k dielectric ?lm HfO2,” Proceedings of SPIE, 2008, 1 Page.


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McIvor et al., “Preparation and Toxicity of Some Alkyl Thiopyrophosphates”, Canadian 1. Chemistry, vol. 34, pp. 1825 1827, 1956. Min et al. “Atomic Layer Deposition of TiN Films by Alternate Supply of Tetrakis (ethylmethylamino)-Titanium and Ammonia” J'. Appl. Phys. vol. 37 (1998) 4999-5004. Morishita et al., “New Substances for Atomic-Layer Deposition of Silicon Dioxide”, J'. Non-Crystalline Solids, vol. 187, pp. 66-69, 1995. Nugent et al., Some Bis(tert-butylimido) Complexes of the Group 6 Transition Metals and a Related Alkylamido Derivativez, Inorg. Chem., vol. 19, pp. 777-779, 1980. Okamoto et al., “Convenient Synthetic Route to Mono-Or Dialkyl Phosphate from Inorganix Phosphorus Acids”, Phosphorus, Sulfur and Silicon, vol. 55, pp. 195-200, 1991. Ott, et al., “Modi?cation of Porous Alumina Membranes Using A12O3 Atomic Layer Controlled Deposition,” Chem. Matter, 1997, 9, pp. 707-714, 8 pages. Park et al., “Mass-Productive Ultra-Low Temperature ALD SiO2 Process Promising for Sub 90nm Memory and Logic Devices”, Pre sented at IEEE IEDM (International Electronic Devices Meeting), San Francisco, CA, Dec. 9-11, 2002, 4 pages. Puurunen, “Surface Chemistry of Atomic Layer Deposition: A Case Study for the Trimethyaluminum/Water Process,” Journal of Applied Physics 97, 121301-1-121301-52, 2005.

Qi et al. Abstract for “High-K gate dielectrics,” Proceedings of SPIE, 1999, 1 Page. Ritala et al., “Atomic Layer Deposition of Oxide Thin Films With Metal Alkoxides as Oxygen Sources”, Science, vol. 288, pp. 319-321, 2000. Ritala, “Advanced ALE processes of amorphous and polycrystalline ?lms”, Applied Surface Science, vol. 112, pp. 223-230, 1997. Sun et al. “Interfacial silicon oxide formation during synthesis of ZrO2 on Si(100)” Applied Surface Science 161 (2000) 115-122. Sundermeyer, “Neue Organometall-Imide des Molybdans und Wolframsidie direkte Einfuhrung der Cyclopentadienyl-Gruppe durch Maskierung der hohen Oxidationsstufe,” Chem. Ber, 124, 1991, pp. 1977-1979. Voronikov, et al., “Reaction of TRIS (Trimethylsilyl) Phosphate With Salts ofInorganic and Organic Acids,” UDS 542.91 :547. 1‘128‘1 18, 1 page, 1978. Yamaguchi et al., “Atomic-Layer Chemical-Vapor-Deposition of Silicon Dioxide Films With an Extremely LoW Hydrogen Content”, Applied Surface Science, vols. 130-132, pp. 202-207, 1998. ZWierZak et al., “Organophosphorus Estersit-Butyl as Protecting Group lin Phosphorylation via Nucleophilic Displacement”, Tetra hedron, vol. 27, pp. 3163-3170, 1971.

* cited by examiner


US. Patent Dec. 18, 2012 Sheet 1 of3 US 8,334,016 B2



02


US 8,334,016 B2 1

VAPOR DEPOSITION OF METAL OXIDES, SILICATES AND PHOSPHATES, AND

SILICON DIOXIDE

RELATED APPLICATIONS

This application claims the bene?t of the ?ling date of US. patent application Ser. No. 11/199,032, noW issued as US. Pat. No. 7,507,848, ?led on Aug. 8, 2005, Which claims the bene?t of the ?ling date of US. patent application Ser. No. 10/381,628, noW issued as US. Pat. No. 6,969,539, Which is the national stage application of PCT Application No. US01/ 30507, ?led on Sep. 28, 2001, Which claims the bene?t ofthe ?ling date of US. Provisional Patent Application Nos. 60/236,283, ?led Sep. 28,2000 and 60/253,917, ?led on Nov. 29, 2000, the contents of Which are hereby incorporated by reference herein in their entireties.

STATEMENT AS TO FEDERALLY SPONSORED RESEARCH

This invention Was made With the support of the United States government under National Science Foundation Grant No. ECS-9975504. The United States has certain rights in the invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention This invention relates to novel reagents for use in thin ?lm

deposition processes such as chemical vapor deposition (CVD) and atomic layer deposition (ALD). These reagents can be used for deposition of materials containing silicon and/or phosphorus along With metals and/or oxygen, com monly called metal oxides, silicates or metal phosphates, or silicon dioxide.

2. Description of the Related Art Chemical vapor deposition (CVD) is a Widely-used pro

cess for forming solid materials, such as coatings or poWders, from reactants in the vapor phase. Comprehensive revieWs of CVD processes have been given recently in C VD ofNonmel als, W. S. Rees, Jr., Editor, VCH Publishers, Weinheim, Ger many, 1996; CVD ofCompound Semiconductors, A. C. Jones and P. O’Brien, VCH, 1996; and The Chemistry ofMeZal C VD, T. Kodas and M. Hampden-Smith, Editors, VCH, 1994.

In CVD processes, a reactant vapor or vapor mixture is brought into contact With a heated surface on Which a thin ?lm is deposited. In a related form of CVD, tWo reactant vapors are alternately exposed to the heated surface. This form of CVD is often called atomic layer deposition (ALD). For suitable reactants, ALD can provide improved step coverage and thickness uniformity compared to CVD With mixed vapors. For a revieW ofALD, see the paper by Mikko Ritala in AppliedSuiy’ace Science, volume 112, pages 223-230 (1997).

Coatings of metal silicates have many applications or potential applications. For example, silicates of Zirconium, hafnium, yttrium or lanthanum are being considered as poten tial replacements for silicon dioxide in gate insulators in silicon semiconductor technology. See, for example, A. Kin gon et al., Nature, volume 406, pages 1032-1038 (2000). In Science, (volume 288, pages 319 to 321 (2000)), Ritala et al. report the use of the sequential ALD reaction of metal chlo rides and silicon alkoxides to produce metal silicates, includ ing Zirconium silicate. HoWever, this reaction deposits ?lms containing residual chlorine, Which can be deleterious to the properties of the ?lm or to its adhesion to substrates or sub sequent coatings. The chlorine in the precursors can also

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2 corrode metal substrates or the apparatus used for the depo sition. Thus it Would be advantageous to have chlorine-free precursors for CVD or ALD of metal silicates or oxides. ALD of silicon dioxide has been achieved by Klaus et al.,

US. Pat. No. 6,090,442 (2000), but the deposition rate is very sloW and the substrate temperature is limited to values near room temperature.

Lithium phosphate is a material of current interest as a lithium ion conductor in lithium batteries. Currently there is no knoWn process for CVD or ALD of lithium phosphate.

SUMMARY OF THE INVENTION

A principal feature of the present invention includes vola tile chemical precursors With reactivity adapted for CVD or ALD of metal silicates, phosphates or oxides. An advantage of these chemical precursors is that they do

not contain chlorine, and leave no chlorine residue during a process for the CVD or ALD of metal silicates, phosphates or oxides. A related feature of the present invention is the deposition

of metal silicates under conditions that produce a sharp inter face betWeen silicon substrates and the deposited metal sili cate.

An advantage of the process is that it permits deposition of materials containing metal silicates or phosphates by a CVD process in Which all the reactants may be mixed homoge neously before delivery to the heated surface of the substrate. An additional advantage of the process is the vapor depo

sition of metal silicates or phosphates With relatively ?xed ratio of metal to silicon over a range of conditions such as concentrations of reactants and position of the substrate inside the reactor.

Another advantage of the invention is its ability to make conformal coatings over substrates With narroW holes, trenches or other structures. This ability is commonly knoWn as good step coverage.

Another feature of the present invention is the preparation of material comprising lithium phosphate. An advantage of the invention is that the reactants are

stable and relatively nonhaZardous. Another feature of the invention includes a chemical vapor

deposition or atomic layer deposition process for metal oxides or mixtures of metal oxides. A further feature of the invention includes process for

atomic layer deposition of silicon dioxide. One particular feature of the present invention includes a

process for depositing oxides or silicates of Zirconium, hafnium, yttrium and/or lanthanum having high dielectric constants of use as gate insulators or trench capacitors in microelectronic devices.

Another particular feature of the present invention includes a process for depositing silicon dioxide or metal silicates having useful optical properties, such as in planar Waveguides and multiplexers/demultiplexers, and in optical interference ?lters. An additional feature of the present invention includes a

process for depositing lithium phosphate coatings alloWing rapid diffusion of lithium for use as separators in batteries or electrochromic devices.

Other features and advantages of the invention Will be obvious to those skilled in the art on reading the instant invention.

In one aspect of the invention vapors of alkoxysilanols are reacted With the vapors of suitably reactive metal or metalloid compounds, such as metal or metalloid alkylamides, alkyls or


US 8,334,016 B2 3

cyclopentadienyls, to form metal silicates. The reaction may be carried out in a manner to form ?lms.

In at least some embodiments, tris(alkoxy)silanol com pounds have the general formula 1, in Which R” represents hydrogen, alkyl groups, ?uoroalkyl groups or alkyl groups substituted With other atoms or groups, preferably selected to enhance the volatility of the compound, Where R” is any one of R1 through R”. The R” may be the same or different from each other.

In at least some embodiments methyl groups are selected for each of the R” in the general formula 1 given above one obtains a highly preferred compound tris(tert-butoxy)silanol 2, Which may be Written more compactly as (’BuO)3SiOH.

CH3

CH3

Another compound of the invention is tris(tert-pentyloxy) silanol, also knoWn as tris(tert-amyloxy)silanol 3, Which may be Written more compactly as (tAmO)3SiOH.

In at least some embodiments of the invention Di(alkoxy) silanediols such as (“BuO)2Si(OH)2 can also be used, although they are less stable than tris(alkoxy)silanol com pounds in at least some applications. Di(alkoxy)silanediol compounds having the general formula 4 may be used accord ing to the invention, Where R”, represents hydrogen, alkyl

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4 groups, ?uoroalkyl groups or alkyl groups substituted by other atoms or groups, preferably selected to enhance vola tility and stability, and may be the same or different for any R”, and R” is any of R1 through R6 may be the same or different.

In at least some embodiments, the groups R1 for the general formula 1 or Rl-R6 for the general formula 4 may be selected from the group consisting of hydrogen, methyl, ethyl, n-pro pyl and isopropyl groups.

In the foregoing compounds, it is also understood that the alkyl groups R1 through R9 for general formula or R1 through R6 for general formula 4 may be a hydrocarbon having some degrees of unsaturation, e. g., aryl, alkenyl or alkynyl groups.

In at least some embodiments, metal compounds include those that react readily With the slightly acidic protons in silanols. These acidic protons are the ones attached directly to oxygen in the silanol. Metal compounds that generally react With these acidic protons include most metal alkyls and other organometallic compounds, metal alkylamides, and some metal alkoxides. The reactivity of any particular compound can be established readily by mixing it With an alkoxysilanol and analyZing the mixture for products by techniques such as nuclear magnetic resonance (N MR). We have found that compounds that are knoWn to react With Water also generally react With alkoxysilanols.

We have also discovered that the stoichiometry of the deposited metal silicates can be controlled. The silicon/metal ratio may be decreased by replacing some or all of the silanol With Water or an alcohol. Conversely, the silicon/metal ratio may be increased by replacing some or all of the metal source by a suitably reactive silicon-containing compound such as a silicon amide or a silylene. By these methods the composition of the deposited material may be chosen to be any composi tion from pure metal oxide to pure silicon dioxide or any desired silicon/metal ratio in betWeen. The stoichiometry may even be varied during the course of one deposition. For example, in the deposition of a gate insulator for a silicon semiconductor device, it may be desirable to begin the depo sition With a silicon-rich layer close to the silicon surface in order to improve the electrical properties of the interface, folloWed by a metal-rich layer With higher dielectric constant.

In another aspect of the invention, vapors of bis(alkyl) phosphates are reacted With the vapors of reactive metal com pounds, such as metal alkylamides, metal alkyls, metal cyclo pentadienides or metal alkoxides, to form metal phosphates. The reaction may be carried out in a Way that forms ?lms.

In at least some embodiments of the invention, phospho rus-containing precursors include bis(alkyl)phosphates 5 in Which R”, represents hydrogen, alkyl groups, ?uoroalkyl groups or alkyl groups, substituted With other atoms or groups Where R” may be any of R1 through R6. The R” may be the same or different from each other.


US 8,334,016 B2

In at least one embodiment, the phosphorus precursor is diisopropylphosphate, represented by the formula 6.

It is also possible to control the stoichiometry of the metal phosphates. The phosphorus/metal ratio may be decreased by replacing some or all of the bis(alkyl)phosphate With Water or an alcohol. Conversely, the phosphorus/metal ratio may be increased by replacing some or all of the metal source by a suitably reactive phosphorus source. By these methods, the composition of the deposited material may be varied from pure metal oxide to pure phosphorus oxide or any desired phosphorus/metal ratio.

In at least some embodiments, the groups Rl-R6 for the general formula 5 may be selected from the group consisting of hydrogen, methyl, ethyl, n-propyl or isopropyl groups. In the foregoing compounds, it is also understood that the alkyl groups R1 through R9 for general formula 1 or R1 through R6 for general formula 4 may be a hydrocarbon having some degrees of unsaturation, e.g., aryl, alkenylialkynyl groups.

In another aspect of the invention, a process for preparing a material comprising silicon includes exposing a substrate to one or more vapors chosen from the group consisting of alkoxysilanols, alkoxysilanediols and silylenes. In at least some embodiments, the silylene is the compound described by the formula

Where R is an alkyl group, or R is tert-butyl. In one aspect of the invention, a process for forming a

material including phosphorus includes exposing a substrate to one or more vapors chosen from the group consisting of bis(alkyl)phosphates, phosphorus(III) oxide and White phos phorus.

In another aspect of the invention, a process is provided for preparing oxygen-containing materials including exposing a substrate to one or more vapors chosen from the group con

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6 sisting of arene hydrates, such as benZene hydrate, naphtha lene hydrate, or a substituted benZene hydrate or a substituted naphthalene hydrate.

In another aspect of the invention, a process for forming a metal oxide is provided including exposing a heated surface alternately to the vapor of one or more metal amides and then to the vapors of Water or an alcohol.

In at least some embodiments, the alcohol is an arene hydrate, or in at least some embodiments, the metal amide or amides are chosen from Table 1.

In another aspect of the invention, a process for forming material including oxygen and one or more metals is provided by exposing a surface alternately to the vapor of one or more organometallic compounds and to the vapor of an arene hydrate.

In at least one embodiment, the organometallic compounds are chosen from Table 2.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, features, and advantages of the present invention can be more fully appreciated With reference to the folloWing detailed description of the invention When consid ered in connection With the folloWing draWings. The draW ings are presented for the purpose of illustration only are not intended to be limiting of the invention, in Which:

FIG. 1 is a cross-sectional illustration of an atomic depo sition layer apparatus used in the practice of at least one embodiment of the invention;

FIG. 2 is a cross-sectional illustration of an atomic depo sition layer apparatus used in the practice of at least one embodiment of the invention; and

FIG. 3 is a cross-sectional scanning electron micrograph of holes in a silicon Wafer uniformly coated With hafnium diox ide using one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

1. Metal Silicates and Silicon Dioxide. The present invention provides a method for preparing

metal silicates of varying metal and silicon content. The method involves the reaction of a vapor of an alkoxysilanol or alkoxysilanediol With a vapor of one or more metal or metal loid compounds. The compound may be formed as a poWder or as a ?lm on a substrate, and in some embodiments, on a heated substrate. The compound may be formed on a sub strate by mixing the vapors of the alkoxysilanol or alkoxysi lanediol and the metal or metalloid compound prior to depo sition on a substrate. In at least some embodiments, a substrate is alternately exposed to a alkoxysilanol or alkox ysilanediol vapor and a vapor of one or more of a metal or metalloid compound.

Silanol and silanediol reactants are commercially available or may be prepared using conventional or knoWn techniques. Silicon precursor, tris(tert-butoxy)silanol, is commercially available from Aldrich Chemical Company (Milwaukee, Wis.) and Gelest, Inc. (TullytoWn, Pa). Tris(tert-butoxy)sil anol may be prepared as folloWs. First tris(tert-butoxy)chlo rosilane is made by either of the folloWing tWo reactions:

SiCl4+3NaO’Bu—>(’BuO)3SiCl+3NaCl (2)

The tris(tert-butoxy)chlorosilane is then hydrolyZed accord ing to the reaction


US 8,334,016 B2 7

See, Backer et al., Rec. Tray. Chim., volume 61, page 500 (1942). This compound is a solid at room temperature and melts at about 66° C. It sublimes at room temperature at a loW pressure of about 10'4 Torr, and can be distilled at a tempera ture of about 104° C. at a pressure of 20 Torr. It is highly soluble in organic solvents such as mesitylene or tetradecane, so that its vapors can be formed conveniently by ?ash vapor iZation of its solution.

Other tris(tert-alkoxy)silanols may be prepared by similar reactions, by substituting other tertiary alcohols, such as tert pentyl alcohol (also knoWn as tert-amyl alcohol), for tert butanol. Tris(tert-amyloxy)silanol, (tAmO)3SiOH, is a liquid at room temperature, so its vapors can be formed conve niently by ?ash vaporization of the neat liquid. It has a vapor pressure of about 2 Torr at 96° C. It is commercially available from Aldrich Chemical Company.

Silanols and silanediols may be reacted With a metal source to obtain a metal silicate. The metal source may contain one or more metals and the resultant metal silicate may contain one or more metals. In at least some embodiments, metal com pounds include those that react readily With the slightly acidic protons in silanols. These acidic protons are the ones attached directly to oxygen in the silanol. Metal compounds that gen erally react With these acidic protons include most metal alkyls and other organometallic compounds, metal alkyla mides, and some metal alkoxides. The reactivity of any par ticular compound can be established readily by mixing it With an alkoxysilanol and analyZing the mixture for products by techniques such as nuclear magnetic resonance (NMR). We have found that compounds that are knoWn to react With Water also generally react With alkoxysilanols.

The reaction is carried out in the vapor state and may be carried out using CVD or ALD techniques. As is discussed in greater detail beloW, ALD provides control over the deposi tion process and is suitable for use in a Wide range of reaction conditions and reactant reactivity.

The silicon/metal ratio may be increased by replacing some or all of the metal precursor by a suitably reactive silicon compound. Silicon halides such as silicon tetrachlo ride, SiCl4, may be used to increase the silicon content, but they may leave chloride as an impurity in the product, and their reactions may be sloWer than desired. Silicon amides such as tetraisocyanatosilane, tetrakis(dimethylamido)silane or tris(dimethylamido)silane avoid the halogen contamina tion. HoWever, their deposition rates may also be sloWer than desired. Silylenes are more rapidly reactive. For example, the thermally stable silylene 7

Where R is an alkyl group or, in at least some embodiments, is tert-butyl, can be used as a rapidly reacting silicon source in place of part or all of the metal source, in order to increase the silicon/metal ratio.

In at least some embodiments, pure silicon dioxide may be prepared. In anALD system, a pulse of silylene is folloWed by a pulse of oxygen gas, in order to fully oxidiZe the silylene after it has reacted With the surface. Pure silicon dioxide can be deposited rapidly by repeating the pulse sequence of silylene and oxygen. 2. Metal Phosphate and Phosphorus Oxide.

The present invention provides a method for preparing metal phosphates of varying metal and phosphorus content. The method involves the reaction of a vapor of an bis(alkyl) phosphate With a vapor of one or more metal or metalloid

20

25

30

35

40

45

50

55

65

8 compounds. The compound may be formed as a poWder or as a ?lm on a substrate, and in some embodiments, on a heated substrate. The compound may be formed on a substrate by mixing the vapors of the bis(alkyl)phosphate and the metal or metalloid compound prior to deposition on a substrate. In at least some embodiments, a substrate is alternately exposed to a bis(alkyl)phosphate vapor and a vapor of one or more of a metal or metalloid compound.

Bis(alkyl) phosphate reactants are commercially available or may be prepared using conventional or knoWn techniques. Phosphorus precursor, diethylphosphate, is commercially available from a number of chemical companies, including Fisher Scienti?c (Pittsburgh, Pa.) and PfaltZ and Bauer (Waterbury, Conn.). Diethylphosphate may be prepared by the air oxidation of phosphinic acid in ethanol, catalyZed by copper chloride:

See, Y. Okamoto, T. Kusano and S. Takamuku, Phosphorus, Sulfur and Silicon, volume 55, pages 195-200 (1991). An alternative reaction sequence is shoWn for diisopropy

lphosphate and may be used for other precursor compounds by appropriate substitutions for isopropanol.

See, Mclvor et al., Canadian J. Chemistry, volume 34, pages 1825 and 1827.

Diisopropylphosphate may also be prepared by ?rst form ing its potassium salt by the following tWo reactions:

See, A. ZWierak and M. Kluba, Tetrahedron, volume 27, pages 3163 to 3170 (1971). The analogous sodium salt may be prepared by the folloWing tWo reactions:

The precursor diisopropylphosphate may then be liberated from its alkali salt by reaction With hydrochloric acid:

M:Na,K (12)

The above bis(alkyl)phosphates react With a Wide range of metal compounds to form metal phosphates. Metal com pounds that generally react With the acid phosphate protons include most metal alkyls and other organometallic com pounds, metal alkylamides, and some metal alkoxides. The reactivity of any particular compound can be established readily by mixing it With a bis(alkyl)phosphate and analyZing the mixture for products by techniques such as nuclear mag netic resonance (N MR). The reaction is carried out in the vapor state and may be

carried out using CVD or ALD techniques. As is discussed in greater detail beloW, ALD provides control over the deposi tion process and is suitable for use in a Wide range of reaction conditions and reactant reactivity. The phosphorus/metal ratio may be increased by replacing

some or all of the metal precursor by a suitably reactive phosphorus compound. Phosphorus halides such as phospho rus trichloride, PCl3, phosphorus pentachloride, PCl5, or phosphorus oxychloride, POCl3, may be used, but some halo gen impurity may be included in the ?lm. Phosphorus alky


US 8,334,016 B2

lamides such as hexamethylphosphorus triamide, (Me2N)3P, hexamethylphosphorimidic triamide, (Me2N)3P:NH, or hexamethylphosphoramide, (Me2N)3PO, avoid the halogen contamination, but their reactions may be sloW. White phos phorus, P4, and phosphorus(lll) oxide, P406, are more quickly reactive and can be used to increase the phosphorus/ metal ratio in an ALD process. Doses of White phosphorus or phosphorus(lll) oxide generally are folloWed by a pulse of oxygen in order to form fully oxidiZed ?lms.

10 The pho sphorus/ metal ratio of material made by ALD may

be decreased by replacing some of the phosphorus doses by doses of Water or alcohol. 3. Metal Amides, Metal Alkyls and Metal Alkoxides.

In at least some embodiments, metal or metalloid amides are useful in the practice of this invention. Some examples are given in Table 1, as Well as a commercial source and/or literature references for their synthesis. The metalloids referred to in Table 1 are boron, silicon and arsenic.

TABLE 1


Melt. Pt. Vapor Press. Compound 0 C. O C./Torr Reference and/or commercial source

Al(N(SiMe3)2)3 188 Wannagat, J. Organomet. Chem. 33, 1 (1971)

Al2(NEt2)6 liquid Barry & Gordon, 2000 Al2(NEtMe)6 liquid 100/0.25 Barry & Gordon, 2000 Al(NiPr2)3 56-59 Brothers, Organometallics 13, 2792 (1994) Al2(NMe2)6 88-89 90/01 Ruff, JACS 83, 2835 (1961) Al(N(Et)CH2CH2NMe2)(NMe2)2 liquid 65-70/0.3 Barry, Gordon & Wagner, Mat. Res. Soc.

Symp. Proc. 606, 83-89 (2000) As(NMe2)3 —53 55/10 Cowley, JACS 95, 6505 (1973) As(N(Me)(SiMe3))3 11-13 67-70/0.1 Birkofer & Ritter, Chem. Ber. 93, 424

(1960) B(NMe2)3 —10 39/10 Abel et al., J. Chem. Soc. 1964, 5584 B(NEt2)3 95/11 Abel &Armitage J. Organomet. Chem. 5,

326 (1966) Ba(N(SiMe3)2)2 >150 Westerhauser, Inorg. Chem. 30, 96 (1991) Be(NMe2)2 88-90 175/760 Anderson, JACS 74, 1421 (1952) Be(N(SiMe3)2)2 —5, liquid 110/3 Clark & Haaland, Chem. Commun., 1969,

912

Be(TMPD)2 —10, liquid 106/0.001 Noeth & Schlosser, Inorg. Chem. 22, 2700 (1983)

Bi(N(SiMe3)2)3 90 Lappert, J. Chem. Soc, Dalton, 2428(1980) Bi(N(Me)(SiMe3))3 90-92/0.1 Birkofer & Ritter, Chem. Ber. 93, 424

(1960) Ca(N(SiMe3)2)2 >120 Lappert, J. Chem. Soc, Chem. Comm.,

1141 (1990) Cd(N(SiMe3)2)2 liquid Burger, Wannagat,

J. Organomet. Chem. 3, 11(1965) Cd(N’BuSiMe3)2 Fisher &Alyea, Polyhedron 3, 509 (1984) Cd(TMPD)2 Fisher &Alyea, Polyhedron 3, 509 (1984) Ce(N(SiMe3)2)3 95-100/10’4 Bradley, J. Chem. Soc, Dalton 1973, 1021 Ce(NiPr2)3 AngeW. Chem., Int. Ed. Engl. 36,

2480(1997) Co(N(SiBuMe2)2)2 liquid 146/0.085 Broomhall-Dillard & Gordon, 1999 Co(N(SiEtMe2)2)2 liquid 106/0.05 Broomhall-Dillard & Gordon, 1999 Co(N(SiMe3)2)2 >70 50-70/0.01 Chisholm, CVD 1, 49 (1995) Co(N(SiMe3)2)3 86-88 Power, JACS 11, 8044 (1989) Co(N(SiPrMe2)2)2 liquid 106/0.05 Broomhall-Dillard & Gordon, 1999 Cr(N(SiMe3)2)3 120 80/0.005 Bradley, J. Chem. Soc, Dalton 1972, 1580 Cr(NEt2)4 liquid 40-60/10’3 Bradley, Proc. Chem. Soc, London

1963, 305 Cr(NiPr2)3 Bradley & Chisholm, Chem. Comm. 1968,

495

Cr(NMe2)4 Bradley, J. Chem. Soc. A, 1971, 1433 Cu4(N(SiMe3)2)4 >180(d.) 160/0.1 Chisholm, CVD 1, 49 (1995) Er(N(SiMe3)2)3 150-180 Wolczanski,1norg. Chem. 31, 1311 (1992) Eu(N(SiMe3)2)3 160-162 82-84/10’4 Bradley, Chem. Comm. 1972, 349 Fe(N(SiBuMe2)2)2 liquid 130/0.2 Broomhall-Dillard & Gordon, 1999 Fe(N(SiMe3)2)2 5, liquid 80-90/0.01 Chisholm, CVD 1, 49 (1995) Fe(N(SiMe3)2)3 >80 80/0.005 Bradley, J. Chem. Soc, Dalton 1972, 1580 Ga(NMe2)3 91 125/001 Chemat Catalog, Northridge, CA Ga(NEt2)3 Chemat Catalog, Northridge, CA Ga(N(SiMe3)2)3 187 Wannagat, J. Organomet. Chem. 33, 1

(1971) Ga(N’BuSiMe3)3 174-176 CoWley, Inorg. Chem. 33, 3251 (1994) Ga(TMPD)3 130-132 CoWley, Inorg. Chem. 33, 3251 (1994) Ga(N(Me)CH2CH2NMe2)(NMe2)2 liquid 48-55/0.18 Barry, Gordon & Wagner, Mat. Res. Soc.

Symp. Proc. 606, 83-89 (2000) Gd(N(SiMe3)2)3 160-163 80-83/10’4 Bradley, Chem. Comm. 1972, 349 Ge(N(SiMe3)2)2 33 60/0.04 Chisholm, CVD 1, 49 (1995) Ge(NEt2)4 >109 109/2 Chemat Catalog, Northridge, CA


US 8,334,016 B2 1 1 12

TABLE l-continued

Some Volatile Metal or Metalloid Amide

Melt. Pt. Vapor Press. Compound ° C. O C./Torr Reference and/or commercial source

Ge(NMe2)4 14, liquid 203/760 Abel, J. Chem. Soc. 1961, 4933; Chemat Ge(N’Bu2)2 2, liquid Lappert, J. Chem. Soc., Chem. Com. 13, 621(1980) Ge(N’BuSiMe3)2 22 50/004 Lappert, J. Chem. Soc, Dalton Trans. 1977,

2004 Ge(TMPD)2 60-62 70/0.02 Lappert,

J. Chem. Soc., Chem. Com. 13, 621(1980) Hf(NEt2)4 liquid 100/0.84 Bradley, J. Chem. Soc A, 1969, 980 Hf(NEtMe)4 liquid 83/0.05 Becker & Gordon, 2000; Aldrich Hf(NMe2)4 30 70/073 Bradley, J. Chem. Soc. A, 1969, 980 Hg(N(SiMe3)2)2 liquid Earborn, J. Chem. Soc, Chem. Comm.,

1051 (1968) Ho(N(SiMe3)2)3 161-164 80-85/10’4 Bradley, J. Chem. Soc, Dalton 1973, 1021 In(N(SiMe3)2)3 168 Wannagat, J. Organomet. Chem. 33, 1

(1971) In(TMPD)3 Frey et al., Z. Anorg. Allg. Chem. 622,

1060 (1996) KN(S1H6XM62)2 liquid Broomhall-Dillard, Mater. Res. Soc. 606,

139 (2000) KN(SiMe3)2 90-100/10’3 Fieser & Fieser 4, 407 La(N(SiMe3)2)3 145-149 100/10’4 Bradley, J. Chem. Soc, Dalton 1973, 1021 La(N’BuSiMe3)3 146-147 90-95/10’4 Becker, Suh & Gordon, 2000 La(NiPr2)3 Aspinall, J. Chem. Soc, Dalton 1993, 993 La(TMPD)3 137-139 100/10’4 Suh & Gordon, 2000 LiN(SiEtMe2)2 liquid 123/0.2 Broomhall-Dillard, Mater. Res. Soc. 606,

139 (2000) LiN(SiMe3)2 71-72 115/1 Inorg. Synth. 8, 19 (1966) Li(TMPD) Kopka, J. Org. Chem. 52, 448 (1987) Lu(N(SiMe3)2)3 167-170 75-80/10’4 Bradley, Chem. Comm. 1972, 349 Mg(N(SiMe3)2)2 123 Andersen, J. Chem. Soc, Dalton Trans. 1982,

887

Mg(TMPD)2 Eaton, JACS 111, 8016 (1989) Mn(N(SiBuMe2)2)2 liquid 143/0.06 Broomhall-Dillard & Gordon, 1999 Mn(N(SiMe3)2)2 55-60 112-120/0.2 Bradley, Trans. Met. Chem. 3, 253 (1978) Mn(N(SiMe3)2)3 108-110 PoWer, JACS 11, 8044 (1989) Mo(N’BuSiMe3)3 Laplaza, Cummins, JACS 118, 8623

(1996) Mo2(NEt2)6 Chisholm, JACS 98, 4469 (1976) Mo2(NMe2)6 solid 100/10’4 Chisholm, JACS 98,4469 (1976) Mo(NEt2)4 liquid 80-110/10’4 Bradley & Chisholm, J. Chem. Soc. A

1971, 2741 Mo(NMe2)4 solid 40-70/0.1 Bradley & Chisholm, J. Chem. Soc. A

1971, 2741 NaN(Si"BuMe2)2 liquid 189/0.08 Broomhall-Dillard, Mater. Res. Soc. 606,

139 (2000) NaN(SiMe3)2 171-175 170/2 Chem. Ber. 94, 1540 (1961) Nb(N(SiMe3)2)3 solid Broomhall-Dillard & Gordon, 1998 Nb(NEt2)4 liquid Bradley & Thomas, Can. J. Chem. 40, 449

(1962) Nb(NEt2)5 >120 120/0.1 Bradley & Thomas, Can. J. Chem. 40, 449

(1962) Nb(NMe2)5 >100 100/0.1 Bradley & Thomas, Can. J. Chem. 40, 449

(1962) Nd(N(SiMe3)2)3 161-164 85-90/10’4 Bradley, J. Chem. Soc, Dalton 1973, 1021 Nd(NiPr2)3 Bradley,

Inorg. Nucl. Chem. Lett. 12, 735(1976) Ni(N(SiMe3)2)2 liquid 80/0.2 Burger & Wannagat, Mh. Chem. 95, 1099

(1964) Pb(N(SiMe3)2)2 39 60/0.04 Lappert, J. Chem. Soc, Chem. Com. 16,

776 (1980) Pb(N’BuSiMe3)2 22 50/004 Lappert, J. Chem. Soc, Dalton Trans. 1977,

2004

Pr(N(SiMe3)2)3 155-158 88-90/10’4 Bradley, Chem. Comm. 1972, 349 Sb(NMe2)3 liquid 50/0.5 CoWley, JACS 95, 6506 (1973) Sb(N(Me)(SiMe3))3 9-11 78-79/0.1 Birkofer & Ritter, Chem. Ber. 93, 424

(1960) Sc(N(SiMe3)2)3 172-174 Bradley, J. Chem. Soc, Dalton 1972, 1580 SiH2(NMe2)2 —104 93/760 Anderson et al., J. Chem. Soc. Dalton 12,

3061 (1987) SiH(NMe2)3 —90 62/45 Gelest, PfaltZ & Bauer, Strem Catalogs Si(NMe2)4 1-2 196/760 Gordon, Hoffman & RiaZ, Chem. Mater. 2,

480 (1990) Si(NHMe)4 37 45/005 Schmisbaur, Inorg. Chem. 37, 510 (1998) Si(NHn-Pr)4 liquid 75/0.05 Schmisbaur, Inorg. Chem. 37, 510 (1998) Si(NEt2)4 3-4 74/19 Abel et al., J. Chem. Soc. 1965, 62;

Chemat


13 US 8,334,016 B2

14 TABLE l-continued



Si(NCO)4 25-26 40/1 Forbes &Anderson, JACS 62, 761 (1940); Gelest, Petrarch, ShoWa-Denko

Si(NCO)4 25-26 40/1 Forbes &Anderson, JACS 62, 761 (1940); Gelest, Petrarch, ShoWa-Denko

Sm(N(SiMe3)2)3 155-158 83-84/10’4 Bradley, Chem. Comm. 1972, 349 Sn(N(SiMe3)2)2 38 84/004 Chisholm, CVD 1, 49 (1995) Sn(NEt2)4 liquid 90/005 Jones & Lappert, J. Chem. Soc. 1965, 1944 Sn(NMe2)4 liquid 51/0.15 Jones & Lappert, J. Chem. Soc. 1965, 1944 Sn(N’Bu2)2 47 Lappert, J. Chem. Soc, Chem. Com. 13,

621(1980) Sn(N’Bu2)3 Hudson, J. Chem. Soc. Dalton Trans. 1976,

2369 Sn(N’BuSiMe3)2 19, liquid 50/004 Lappert, J. Chem. Soc, Dalton Trans. 1977,

2004

Sn(N’BuSiMe3)3 Hudson, J. Chem. Soc. Dalton Trans. 1976, 2369

Sn(TMPD)2 Lappert, J. Chem. Soc, Chem. Com. 16, 776 (1980)

Sr(N(SiMe3)2)2 164 Westerhauser, Inorg. Chem. 30, 96 (1991) Ta(NEt2)4 120/0.1 Bradley & Thomas, Can. J. Chem. 40, 1355

(1962) Ta(NMe2)5 >180 100/0.1 Bradley & Thomas, Can. J.

Chem. 40, 1355(1962); Strem Ta(N’Bu) (NEt2)3 liquid 90/ 0.1 Inorgtech Ta(NEt)(NEt2)3 liquid 120/0.1 Becke-Goehring & Wunsch, Chem. Ber.

93, 326 (1960) Tb(N(SiMe3)2)3 162-165 78-82/10’4 Wolczanski, Inorg. Chem. 31, 1311 (1992) Th(NEt2)4 40-50/10’4 Reynolds & Edelstein, Inorg. Chem. 16,

2822 (1977) Th(NPr2)4 liquid 60-70/10’4 Reynolds & Edelstein, Inorg. Chem. 16,

2822 (1977) Ti(N(SiMe3)2)3 solid Bradley, J. Chem. Soc, Dalton 1972, 1580 Ti(NEt2)4 liquid 112/0.1 Bradley & Thomas, J. Chem. Soc. 1960,

3857

Ti(NiPr2)3 Kruse, Inorg. Chem. 9, 2615 (1970) Ti(NiPr2)4 82-85 110/0001 Froneman, P, S, Si, Relat. Elem. 47, 273

(1990) Ti(NMe2)4 liquid 50/005 Bradley & Thomas, J. Chem. Soc 1960,

3857

Tl(N(SiMe3)2)3 Allman, J. Organomet. Chem. 162, 283 (1978)

U(N(SiMe3)2)3 137-140 80-100/10’3 Andersen, Inorg. Chem. 18, 1507 (1979) U(NEt2)4 115-125/06 Jones, JACS 78, 4285 (1956) U(NPr2)4 liquid 40-50/10’4 Reynolds & Edelstein, Inorg. Chem. 16,

2822 (1977) V(N(SiMe3)2)3 >95 95/0005 Bradley, J. Chem. Soc, Dalton 1972, 1580 V(NEt2)4 liquid 90/0001 Bradley, Chem. Commun. 1964, 1064 V(NMe2)4 solid 50/0001 Bradley, J. Chem. Soc A, 1969, 2330 V(O)(NMe2)3 40 40/0001 Davidson, Harris & Lappert, JCS Dalton

1976, 2268 W2(NEt2)6 solid 140-170/1041 Chisholm, JACS 97, 5626 (1975); 98, 4477

(1976) W2(NMeEt)6 solid 100-130/10“1 Burger & Wannagat, Monatsh. 95, 1099

(1964) W2(NMe2)6 solid 100-120/1041 Burger & Wannagat, Monatsh. 95, 1099

(1964) W(N’Bu)2(NH’Bu)2 89-90 60-65/10’4 Nugent & HarloW, Inorg. Chem. 19, 777

(1980) W(N’Bu)2(NEtMe)2 liquid 87/0.1 Suh & Gordon, 2000 W(N’Bu)2(NMe2)2 liquid 75/0.1 Suh & Gordon, 2000 Y(N(SiMe3)2)3 180-184 100/10’4 Bradley, J. Chem. Soc, Dalton 1973, 1021;

Alfa Y(N"Pr2)3 Bradley, Inorg. Nucl. Chem. Lett. 12,

735(1976) Y(N’BuSiMe3)3 158-160 90-95/10’4 Suh & Gordon, 2000 Y(TMPD)3 177-179 100/10’4 Suh & Gordon, 2000 Yb(N(SiMe3)2)3 162-165 Bradley, J. Chem. Soc, Dalton 1973, 1021 Yb(NlPr2)3 Bradley, Inorg. Nucl. Chem. Lett. 12, 735

(1976) Zn(N(SiMe3)2)2 liquid 120/0.1 Inorg. Chem. 23, 1972 (1984) Zn(N’Bu2)2 Schumann, Z. Anorg. Allg. Chem. 623,

1881 (1997) Zn(TMPD)2 Schumann, Z. Anorg. Allg. Chem. 623,

1881 (1997)


US 8,334,016 B2 15 16

TABLE l-continued



Zr(NEt2)4 liquid 112/0.1 Bradley & Thomas, J. Chem. Soc. 1960,

Zr(Nl_EtMe)4 liquid 82/0.05 Biscler & Gordon, 2000 Zr(N’Pr2)4 >120 120/0.001 Bradley, Inorg. Nucl. Chem. Lett. 11, 155

Zr(NMe2)4 70 65-80/0.1 l3lrgaflfgy & Thomas, J. Chem. Soc. 1960, 3857

In Table 1, TMPD stands for 2,2,6,6-tetramethylpiperidide. 15 In at least some embodiments, metal alkyls are useful inthe Further examples may be found in the book Metal and Met practice of this invention. Some examples are given in Table alloidAmides, by M. F. Lappert, P. P. Power, A. R. Sanger and . . R_ C_ Srivastava, published in 1980 by Ellis HOrWOOd Ltd” a 2, as Well as a commerclal source or hterature reference of division of John Wiley & Sons. their synthesis.

TABLE 2

Some Volatile Org_anometallic Compounds

Melt. Pt. Vapor Press. Compound ° C. O C./Torr Sources

AlMe3 15.4 20/8 Strem Ba(n-PrMe4Cp)2 liquid Strem Ba(’Pr4Cp)2 149-150 90/001 1. Am. Chem. Soc. 113, 4843-4851 (1991) Ba(Me5Cp)2 265-268 140/0.01 J. Organomet. Chem. 325, 31-37 (1987) BeEt2 12, liquid 110/15 Strem BiMe3 liquid 110/760 PfaltZ & Bauer, Organometallics Ca(’Pr4Cp)2 196-200 190/001 1. Am. Chem. Soc. 113, 4843-4851 (1991) Ca(Me5Cp)2 207-210 90/001 J. Organomet. Chem. 325, 31-37 (1987) CdMe2 —4.5 105.5/760 Strem CeCp3 452 230/001 Strem Ce("PrCp)3 Strem Ce(Me4Cp)3 solid Aldrich CoCp2 176-180 Aldrich, Strem CoCp (CO)2 liquid 37-3 8.5/2 Strem Co(CO)3NO liquid 50/760 Strem CrCp2 168-170 Aldrich, Strem Cr(Me5Cp)2 200 Strem Cr("PrCp)2 solid Strem Cr(EtBZ)2 liquid 140-160/1 Strem CuCpPEt3 solid 60/0.01 Strem Er(Cp)3 285 200/0.01 Strem Er("PrCp)3 63-65 222/10 Aldrich, Alfa, Strem Er(BuCp)3 liquid 240/0.1 Aldrich, Alfa (pyrophoric) Eu(Me4Cp)3 solid Aldrich FeCp (MeZNCHZCp) liquid 91 -92/0.5 Strem FeCp(lBuCp) liquid 80/015 Strem GaMe3 —15, liquid 55.7/760 Strem GdCp3 295 Aldrich, Alfa, Strem Gd(iPrCp)3 liquid 200/0.01 Erbil, U.S. Pat. No. 4,882,206 (1989) InCp3 solid 50/0.01 Strem In(Me5Cp)3 Strem InMe3 88 Strem Ir(MeCp)(1,5-COD) Strem La(lPrCp)3 liquid 180-195/0.01 Strem; Erbil, U.S. Pat. No. 4,882,206 (1989) LaCp3 295 dec. 218/0.1 Aldrich, Alfa, Strem LaCp3(NCCH3)2 162 Inorganica Chim. Acta 100, 183-199 (1985) La(Me2NC2H4Cp)3 75 160/0001 J. Organomet. Chem. 462, 163-174 (1993) Mg(PrCp)2 liquid Strem Mg(EtCp)2 liquid Aldrich, Strem MgCp2 180 160/0.1 Aldrich, Strem MnCp2 175 Aldrich, Strem Mn(EtCp)2 liquid Aldrich (pyrophoric) Mn(Me5Cp)2 292 Strem MO(EtBZ)2 liquid Strem NdCp3 417 220/001 Aldrich, Alfa, Strem Nd(iPrCp)3 solid Aldrich, Alfa, Strem Ni(PF3)4 liquid 70.7/760 Strem PrCp3 427 220/001 Aldrich, Alfa, Strem Pr("PrCp)3 50-54 Aldrich, Alfa, Strem SbEt3 156/760 Strem ScCp3 240 200/0.05 Aldrich, Strem


US 8,334,016 B2 1 7 TABLE 2-continued

18

Some Volatile Org_anometallic Compounds


SmCp3 356 220/001 Strem Sm("PrCp)3 Zh. Neorg. Khim. 27, 2231-4 (1982) Sr("Pr4Cp)2 151-153 Chem. Rev. 93, 1023-1-36 (1993) Sr(Me5Cp)2 216-218 J. Organomet. Chem. 325, 31-37 (1987)

solid Aldrich, Strem TmCp3 solid Strem Tm("PrCp)3 MRS Symp. Proc. 301, 3-13 (1993) TICp solid 75/0.1 Strem VCp2 165-167 200/0.1 Aldrich, Strem V(EtCp)2 liquid Aldrich W(lI’rCp)2H2 liquid 122-125/0.1 Aldrich, Strem YCp3 296 200/2 Alfa, Strem Y(MeCp)3 Strem Y("PrCp)3 Strem Y(BuCp)3 liquid Aldrich, Alfa, Strem YbCp3 277 150(vac.) Strem Yb(iPrCp)3 47 Zh. Neorg. Khim. 27, 2231-4 (1982) ZnEt2 —28, liquid 124/760 Aldrich, Strem ZnMe2 —42, liquid 46/760 Aldrich, Strem ZrCp2Me2 170 Aldrich, Strem Zr(’BuCp)2Me2 Strem

In Table 2, Cp is an abbreviation for cyclopentadienide, Me5 Cp represents pentamethylcyclopentadienide, l‘PrCp repre sents isopropylcyclopentadienide, l'PrMe4 Cp stands for iso propyltetramethylcyclopentadienide, l'Pr4 Cp stands for tet raisopropylcyclopentadienide, EtCp stands for ethylcyclopentadienide, PrCp stands for propylcyclopentadi enide, l‘PrCp stands for isopropylcyclopentadienide, BuCp stands for butylcyclopentadienide, BZ for benZenide, EtBZ for a mixture of isomers of ethylbenZenide and 1,5-COD for 1,5 -cyclooctadienide.

In at least some embodiments, metal or metalloid alkoxides can be used in the practice of this invention. Suitable com pounds are listed in Table 3, as Well as a commercial source or a literature reference of their synthesis.

TABLE 3

Some Volatile Metal or Metalloid Alkoxides


Al2Et3(O-sec-Bu)3 liquid 190/0.1 Strem B(OMe)3 —29, 68.7/760 Aldrich, Rohm and

liquid Haas, Strem Hf(O’Bu)4 liquid 90/5 Strem Nb(OEt)5 6, liquid 156/0.05 Aldrich, Chemat,

Strem

Ta(OEt)5 21 146/0.15 Aldrich, Chemat, Strem

Ti(O"Pr)4 20 58/1 Aldrich, Chemat, DuPont, Strem

Y(OCMe2CH2NMe2)3 liquid 80/0.001 Herrmann, Inorg. Chem. 36, 3545-3552 (1997)

Zr(O’Bu)4 liquid 81/3, 90/5 Aldrich, Strem

Metal halides may also be used in the practice of this inven tion, but they have the disadvantages that they tend to leave some halide impurity in the ?lm and cause corrosion of sub strates or apparatus. 4. Reactions With Water and Alcohols.

In at least some embodiments, part of the silanol or phos phate is replaced With Water in order to deposit metal-rich silicates and phosphates. In a CVD reactor, Water vapor tends to react very quickly With the vapors of the metal precursors

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near the vapor entrance to produce poWder, rather than ?lm on the substrate. In anALD reactor such premature reactions are avoided because the reactants are introduced alternately into the reactor, so reactions near the entrance are prevented and reaction is con?ned to the surface of the substrate. However, Water tends to adsorb strongly on surfaces, so it can take a long time to purge the ALD reactor between pulses of the reactants.

Alcohols such as isopropanol and tert-butanol can alleviate these problems With Water, since the reactions of alcohols With metal compounds are sloWer, and the more volatile alco hols can be pumped more quickly from an ALD reactor. Alcohols such as isopropanol and tert-butanol are particularly appropriate for reactions involving thermally liable metal compounds. In some cases the substrate temperature is raised in order to decompose alkyl alcohols and thereby remove their carbon content from the ?lm. A thermally labile metal compound may self-decompose at higher substrate tempera tures, so self-limiting ALD reactions cannot be achieved.

The arene hydrates are a class of alcohols that decompose at loWer temperatures than ordinary alkyl alcohols, and thus can be used to provide carbon-free metal oxides at loW enough temperatures to avoid self-decomposition of even thermally labile metal compounds. For example, benZene hydrate decomposes easily to Water and benZene because of the aromatic stabilization of the benZene byproduct:

HO

O _> H2O +

Other examples of useful arene hydrates are alkyl-substituted benZene hydrates such as the various isomers of toluene hydrate:

(13)


US 8,334,0l6 B2 19

-continued

Other useful alcohols include the tWo naphthalene hydrates

Eco 5@ and alkyl-substituted naphthalene hydrates such as methyl naphthalene hydrate. Thus arene alcohols may be used in the reaction of metal compounds at moderate deposition condi tions. In particular, it can be used for the formation of metal oxides, or for the formation of metal silicates or metal pho phates When used in combination With the silicon and phos phorus precursors described herein.

In at least some embodiments of the present invention, a metal oxide is obtained by reaction of a metal amide With Water. Suitable metal amides include any of those listed in Table 1. Thus, by Way of example, hafnium oxide Was pre pared by ALD using Water vapor and tetrakis(dimethylamido) hafnium. This ALD reaction Was found to be surprisingly ef?cient, in that almost all of the precursor that Was delivered into the reaction chamber Was deposited as ?lm on the sub strate and on the exposed Wall of the chamber. It Was also found to be surprisingly fast, going to completion (saturation of the surface reaction on a ?at surface) With less than 50 Langmuirs of vapor ?ux (l Langmuir is the ?ux delivered to a surface in one second by a partial pressure of 10'6 Torr of the precursor). The byproducts of the reaction Were found to consist of dimethylamine vapor, Which does not etch the deposited hafnium oxide ?lm. Most surprisingly, the use of tetrakis(alkylamido)hafnium precursors succeeded in the ALD of highly uniform ?lms of hafnium oxide even in holes With very high aspect rations (over 40). By Way of contrast, the reactants commonly used in the prior art for ALD of hafnium oxide, HfCl4 and Hf(O-tert-Bu)4, have not suc ceeded in the uniform deposition of HfO2 in holes With such high aspect ratios.

VaporiZation of Reactants and Product Deposition. Vapors of liquidprecursors may be formed by conventional

methods, including heating in a bubbler, in a thin-?lm evapo rator, or by nebuliZation into a carrier gas preheated to about 100 to 2500 C. The nebuliZation may be carried out pneumati cally or ultrasonically. Solid precursors may be dissolved in organic solvents, including hydrocarbons such as decane, dodecane, tetradecane, toluene, xylene and mesitylene, and With ethers, esters, ketones and chlorinated hydrocarbons. Solutions of liquid precursors generally have loWer viscosi ties than the pure liquids, so that in some cases it may be preferable to nebuliZe and evaporate solutions rather than the pure liquids. The liquids or solutions can also be evaporated With thin-?lm evaporators or by direct injection of the liquids into a heated Zone. Thin-?lm evaporators are made by Artisan Industries (Waltham, Mass.). Commercial equipment for direct vaporization of liquids is made by MKS Instruments (Andover, Mass.), ATMI, Inc. (Danbury, Conn.), Novellus Systems, Inc. (San Jose, Calif.) and COVA Technologies

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20 (Colorado Springs, Colo.). Ultrasonic nebuliZers are made by Sonotek Corporation (Milton, N.Y.) and Cetac Technologies (Omaha, Nebr.). The silicon precursors of the present invention may be

reacted With metal or metalloid amides, such as those in Table l, to form metal or metalloid silicates. The silicon precursors of the present invention may be reacted With organometallic compounds, such as those in Table 2, to form metal silicates. The silicon precursors of the present invention may be reacted With metal or metalloid alkoxides, such as those in Table 3, to form metal or metalloid silicates. The silicon precursors of the present invention may also be reacted With other suitably reactive metal compounds to form metal silicates. For example, tris(tert-butoxy)silanol may be reacted With tris (tert-butyl(trimethylsilyl)amido)yttrium (Table l) to form yttrium silicate (Examples 5 and 6). Also, tris(tert-butoxy) silanol may be reacted With tris(tert-butyl(trimethylsilyl) amido)lanthanum (Table l) to form lanthanum silicate (Ex amples 7 and 8). Metal oxides may be obtained by reactin of a suitable metal and With Water. Tris(bis(trimethylsilyl)ami do)lanthanum reacts With Water vapor to form a more lantha num-rich silicate (Example 21). Lanthanum oxide may be deposited from silicon-free precursors such as tris(2,2,6,6 tetramethylpiperidido)lanthanum (Example 22). The phosphorus precursors of the present invention may be

reacted With suitably reactive metal compounds, such as those in the Tables, to form metal phosphates. For example, diisopropylphosphate may be reacted With lithium bis(eth yldimethylsilyl)amide (Table l) to provide a process for depositing lithium phosphate ?lms that are lithium ion con ductors, as is shoWn in Examples 9 and 10. The process of the invention can be carried out in standard

equipment Well knoWn in the art of chemical vapor deposition (CVD). The CVD apparatus brings the vapors of the reactants into contact With a heated substrate on Which the material deposits.A CVD process can operate at a variety of pressures, including in particular normal atmospheric pressure, and also loWer pres sures. Commercial atmospheric pres sure CVD fur naces are made in the USA by the Watkins -Johnson Company (Scotts Valley, Calif.), BTU International (North Billerica, Mass.) and SierraTherm (Watsonville, Calif.). Commercial atmospheric pressure CVD equipment for coating glass on the ?oat production line is made in the USA by Pilkington North America (Toledo, Ohio), PPG Industries (Pittsburgh, Pa.) and AFG Industries (Kingsport, Tenn.). LoW-pressure CVD equipment is made by Applied Materials (Santa Clara, Calif.), Spire Corporation (Bedford, Mass.), Materials Research Corporation (Gilbert, AriZ.), Novellus Systems, Inc. (San Jose, Calif.), Genus (Sunneyvale, Calif.), Mattson Technology (Frement, Calif.), Emcore Corporation (Somer set, N.J.), NZ Applied Technologies (Wobum, Mass.), COVA Technologies (Colorado Springs, Colo.) and CVC Corpora tion (Freemont, Calif.). Apparatus adapted to atomic layer deposition (ALD) is available from Genus (Sunneyvale, Calif.) and ASM Microchemistry (Espoo, Finland). The process of the invention may also be carried out using

atomic layer deposition (ALD). ALD introduces a metered amount of a ?rst reactant component into a deposition cham ber having a substrate therein for layer deposition. A thin layer of the ?rst reactant is deposited on the substrate. After a preselected time period, a metered amount of a second reac tant component is then introduced into the deposition cham ber, Which is deposited on and interacts With the already deposited layer of the ?rst reactant component. Alternating layers of ?rst and second reactant components are introduced into the deposition chamber and deposited on the substrate to form a layer of controlled composition and thickness. Alter


US 8,334,016 B2 21

nation of deposition may be on the order of seconds to min utes and is selected to provide adequate time for the just introduced component to deposit on the substrate and for any excess vapor to be removed from the headspace above the substrate. It has been determined that the surface reactions are self-limiting so that a reproducible layer of predictable com position is deposited. Use of more than tWo reactant compo nents is Within the scope of the invention.

In at least some embodiments of the invention, automobile fuel injectors (Ford model CM-4722 F13Z-9F593-A) may be used to deliver pulses of the solutions of precursors into the nitrogen carrier gas. Solution is delivered each time a valve opens for about 50 milliseconds.

In another embodiment of the invention, 6-port sampling valves (Valco model EP4C6WEPH, Valco Instruments, Houston, Tex.) normally used for injecting samples into gas chromatographs may be used to deliver pulses of solutions into a suitable carrier gas. Each time that a valve is opened, solution ?oWs into a tube in Which solution is vaporized by heat from hot oil ?oWing over the outside of the tube. Carrier gas moves the vapor from the tube into the ADD reactor tube.

In at least some embodiments, a layer is deposited by ALD using an apparatus such as that illustrated in FIG. 1. Accord ing to at least some embodiments, measured doses of reactant vapor 30 are introduced into the heated deposition chamber 110 by the use of a pair of air-actuated diaphragm valves, 50 and 70 (Titan II model made by Parker-Hanni?n, Richmond Calif). The valves are connected by a chamber 60 having a measured volume V, and this assembly is placed inside an oven 80 held at a controlled temperature T2. The pressure of the reactant vapor 30 in the precursor reservoir 10 is equal to the equilibrium vapor pressure Peq of the solid or liquid reac tant 20 at a temperature Tl determined by the surrounding oven 40. The temperature T 1 is chosen to be high enough so that the precursor pres sure Peq is higher than the pres sure P dep in the deposition chamber. The temperature T2 is chosen to be higher than T 1 so that only vapor and no condensed phase is present in the valves 50 and 70 or the chamber 60. In the case of a gaseous reactant, its pressure can be set by a pressure regulator (not shoWn) that reduces its pressure from the pres sure in the precursor gas cylinder 10. A similar arrangement is provided for each reactive pre

cursor introduced into the deposition chamber 110. Thus, a precursor reservoir 11 holds a solid or liquid reactant 21 having a vapor pres sure 31 at a temperature T 1' maintained by surrounding oven 41. Valves 51 and 71 are connected by a chamber 61 having a measured volume V' and this assembly is housed in oven 81 at temperature T2‘.

Carrier gas (such as nitrogen) ?oWs at a controlled rate into inlet 90 in order to speed the How of the reactants into the deposition chamber and the purging of reaction byproducts and un-reacted reactant vapor. A static mixer may be placed in the tubing 100 leading into the reactor, to provide a more uniform concentration of the precursor vapor in the carrier gas as it enters the deposition chamber 110 heated by furnace 120 and containing one or more substrates 130. The reaction byproducts and un-reacted reactant vapors are removed by trap 140 before passing into a vacuum pump 150. Carrier gas exits from exhaust 160.

In operation, valve 70 is opened so that the pressure inside chamber 60 is reduced to a value P dep close to that of the deposition chamber 110. Then valve 70 is closed and valve 50 is opened to admit precursor vapor from precursor reservoir 10 into chamber 60. Then valve 50 is closed so that the volume V of chamber 60 contains vapor of the precursor at a pressure Peq. Finally, valve 70 is opened to admit most of the precursor vapor contained in chamber 60 into the deposition

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22 chamber. The number of moles, n, of precursor delivered by this cycle can be estimated by assuming that the vapor obeys the ideal gas laW:

Where R is the gas constant. This expression also assumes that carrier gas from tube 90 does not enter chamber 60 through valve 70 during the brief time that it is open to release the precursor vapor. If mixing of carrier gas With the precursor vapor does occur during the time that valve 70 is open, then a larger dose of precursor vapor may be delivered, up to a maximum value

if all the residual precursor vapor in chamber 60 is displaced by carrier gas. For precursors With relatively high vapor pres sure (Peq>>Pdep), there is not much difference betWeen these tWo estimates of the precursor dose.

This cycle of delivering precursor 20 is repeated if neces sary until the required dose of precursor 20 has been delivered into reaction chamber. Normally, in anALD process, the dose of precursor 20 delivered by this cycle (or several such cycles repeated to give a larger dose) is chosen to be large enough to cause the surface reactions to go to completion (also called

“saturation”). Next a dose of vapor 31 from a second precursor 21 may be

measured and delivered by a similar apparatus With compo nents numbered similarly to the apparatus for the ?rst precur sor 20.

In the case of precursors With vapor pressure so loW that Peq is less than Pdep, this method Will not deliver any precursor vapor into the deposition chamber. The vapor pressure can be increased by raising the temperature T1, but in some cases a higher temperature Would result in thermal decomposition of the precursor. In such cases of thermally sensitive precursors With loW vapor pressure, vapor may be delivered using the apparatus in FIG. 2. The chamber 220 is ?rst pressurized With carrier gas delivered through tube 240 and valve 200 from a pressure controller (not shoWn). Valve 200 is then closed and valve 210 opened to alloW the carrier gas to pressurize pre cursor reservoir 220 to pressure PM. The mole fraction of precursor vapor in the vapor space 30 of reservoir 10 is then Peg/Pm. If PM is set to a pressure larger than the pressure P dep in the deposition chamber, then the number of moles deliv ered in a dose can be estimated from the equation

Where V is the volume of the vapor space 30 in chamber 10. This dose is delivered by opening valve 230. If carrier gas from tube 90 enters the volume 30 during the time that the valve 230 is open, then a dose someWhat larger than this estimate may be delivered. By making the volume V large enough, a precursor dose that is certainly large enough to saturate the surface reaction may be delivered. If the vapor pressure Peq is so loW that the required volume V Would be impracticably large, then additional doses from volume V may be delivered before delivering a dose of the other reac tant.

A similar apparatus is provided for each precursor reactant of the system. Thus, chamber 221 is ?rst pressurized With carrier gas delivered through tube 241 and valve 201 from a pressure controller (not shoWn). Valve 201 is then closed and valve 211 is opened to alloW the carrier gas to pressurize precursor reservoir 11 to pressure PM. This dose is delivered by opening valve 231. Carrier gas from tube 91 promotes transport of the metered dose to the deposition chamber.


US 8,334,016 B2 23

In an isothermal deposition Zone, material is generally deposited on all surfaces exposed to the precursor vapors, including substrates and the interior chamber Walls. Thus it is appropriate to report the precursor doses used in terms of moles per unit area of the substrates and exposed chamber Walls.

The liquids and solutions described herein may also be used as metal-containing precursors for other types of depo sition processes, such as spray coating, spin coating or sol-gel formation of mixed metal oxides. The high solubility and miscibility of these precursors is an advantage in forming the required solutions.

The amides disclosed in these examples appeared to be non-pyrophoric by the methods published by the United States Department of Transportation. One test calls for plac ing about 5 milliliters of the material on an non-?ammable porous solid, and observing that no spontaneous combustion occurs. Another test involves dropping 0.5 milliliters of the liquid or solution on a Whatman No. 3 ?lter paper, and observing that no ?ame or charring of the paper occurs.

The precursors generally react With moisture in the ambi ent air, and should be stored under an inert, dry atmosphere such as pure nitrogen gas. The invention may be understood With reference to the

folloWing examples Which are for the purpose of illustration only and Which are not limiting of the invention, the full scope of Which is set forth in the claims Which folloW.

Example 1

CVD of Zirconium Silicate

A solution (1% by Weight) of tris(tert-butoxy)silanol in mesitylene Was pumped at a rate of 6 ml/hour into a 1/16" OD. tee joint through Which nitrogen gas ?oWed at 0.4 L/min. The resulting fog ?oWed into a tube heated to 2500 C. A solution (1% by Weight) of tetrakis(ethylmethylamido)Zirconium in mesitylene Was pumped at a rate of 12 ml/hour into another tee joint through Which nitrogen gas ?oWed at 0.4 L/min. The resulting fog ?oWed into the same heated tube. The gas pres sure Was maintained at 5 Torr by a vacuum pump attached to the outlet of the glass tube by a liquid nitrogen trap. Substrates of silicon and glassy carbon placed inside the tube Were coated With a ?lm of Zirconium silicate Whose thickness varied along the length of the tube. Analysis of the ?lm by Rutherford backscattering spectroscopy gave a composition ZrSi2O6 for ?lms deposited on glassy carbon. No carbon or nitrogen Was detected in the ?lm. The refractive indexes of ?lms deposited on silicon Were found to be about 1.6 by ellipsometry.

Example 2

ALD of Zirconium Silicate

Example 1 Was repeated except that the precursors Were injected in alternate pulses spaced 5 seconds apart, instead of continuously. A ?lm of similar composition, ZrSi2O6, Was deposited With uniform thickness along the Whole length of the heated Zone. The thickness Was about 0.3 nm per cycle.

Example 3

CVD of Hafnium Silicate

Example 1 Was repeated With tetrakis(ethylmethylamido) hafnium in place of tetrakis(ethylmethylamido)Zirconium.

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24 Films of composition approximately HfSi2O6 Were formed. No carbon or nitrogen Was detected in the ?lm. The refractive indexes of ?lms deposited on silicon Were found to be about 1.6 by ellipsometry.

Example 4

ALD of Hafnium Silicate

Example 3 Was repeated except that the precursors Were injected in alternate pulses spaced 5 seconds apart, instead of continuously. A ?lm of similar composition, HfSi2O6, Was deposited With uniform thickness along the Whole length of the heated Zone. The thickness Was about 0.3 nm per cycle.

Example 5

CVD of Yttrium Silicate

Example 1 Was repeated With tris(tert-butyl(trimethylsilyl) amido)yttrium in place of tetrakis(ethylmethylamido)Zirco nium. Films of composition approximately Y2Si2O7 Were formed. No carbon or nitrogen Was detected in the ?lm. The refractive indexes of ?lms deposited on silicon Were found to be about 1.6 by ellipsometry.

Example 6

ALD of Yttrium Silicate

Example 5 Was repeated except that the precursors Were injected in alternate pulses spaced 5 seconds apart, instead of continuously. A ?lm of similar composition, Y2Si2O7, Was deposited With uniform thickness along the Whole length of the heated Zone. The thickness Was about 0.3 nm per cycle. Composition approximately Y2Si2O7.

Example 7

CVD of Lanthanum Silicate

Example 1 Was repeated With tris(bis(trimethylsilyl)ami do)lanthanum in place of tetrakis(ethylmethylamido)Zirco nium and tetradecane in place of mesitylene. Films With a LazSi ratio of about 0.9 Were formed on a glassy carbon substrate at a substrate temperature of 2500 C. No carbon or nitrogen Was detected in the ?lms.

Example 8


Example 7 Was repeated except that the precursors Were injected in alternate pulses spaced 5 seconds apart, instead of continuously. A ?lm of similar composition Was deposited With uniform thickness along the Whole length of the heated Zone.

Example 9

CVD of Lithium Phosphate

Liquid lithium bis(ethyldimethylsilyl)amide (1 part by Weight) Was mixed With mesitylene (99 parts). The resulting solution Was nebuliZed by pumping at a rate of 12 ml/hour into a tee joint into nitrogen gas ?oWing at 0.30 L/min into the deposition Zone inside a tube (24 mm inside diameter) in a


US 8,334,016 B2 25

furnace heated to 2500 C. Simultaneously a 1% mesitylene solution of diisopropylphosphate Was similarly nebuliZed into another nitrogen carrier gas stream ?owing at 0.30 L/min into the same tube furnace. The gas pressure Was maintained at 5 Torr by a vacuum pump attached to the outlet of the glass tube by a liquid nitrogen trap. A thin ?lm Was deposited on a silicon substrate placed on the bottom of the glass tube, as Well as on the inside of the tube. The thickness pro?le shoWed a peak near the gas entrance to the tube furnace. The ?lm Was analyZed by X-ray photoelectron spectroscopy to contain lithium, phosphorus and oxygen.

Example 10

ALD of Lithium Phosphate

Example 9 Was repeated With the change that the materials Were introduced in alternating pulses spaced 5 seconds apart in time. A similar lithium phosphate ?lm Was deposited, except that the thickness Was nearly constant throughout the deposition Zone.

Comparative Example 1

Control deposition With only tris(tert-butoxy)silanol

Example 1 Was repeated using only the silicon precursor and no Zirconium precursor. No ?lm Was deposited.


Control deposition With only tetrakis(ethylmethylamido)Zirconium

Example 1 Was repeated using only the Zirconium precur sor and no silicon precursor. No ?lm Was deposited.


Control deposition With only tetrakis(ethylmethylamido) hafnium

Example 3 Was repeated using only the hafnium precursor and no silicon precursor. No ?lm Was deposited.


Control deposition With only tris(tert-butyl(trimethylsilyl)amido)yttrium

Example 5 Was repeated using only the yttrium precursor and no silicon precursor. No ?lm Was deposited.


Control deposition With only tris(bis(trimethylsilyl)amido) lanthanum

Example 7 Was repeated using only the lanthanum precur sor and no silicon precursor. No ?lm Was deposited.


Control deposition With only diisopropylphosphate

Example 9 Was repeated using only the phosphorus pre cursor and no lithium precursor. No ?lm Was deposited.

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26 Comparative Example 7

Control deposition With only lithium bis(ethyldimethylsilyl)amide

Example 9 Was repeated using only the lithium precursor and no phosphorus precursor. No ?lm Was deposited.

Example 11

ADL formation of Metal Silicates and Phosphates

The ALD examples 2, 4, 6, 8 and 10 Were repeated using automobile fuel injectors (Ford model CM-4722 F13Z 9F593-A) to deliver pulses of the solutions of precursors into the nitrogen carrier gas. About 0.05 m of solution Was deliv ered each time that a valve Was opened for about 50 millisec onds. Similar results Were obtained. The ALD examples 2, 4, 6, 8 and 10 Were repeated using a

6-port sampling valves (Valco model EP4C6WEPH, Valco Instruments, Houston, Tex.) normally used for injecting samples into gas chromatographs to deliver pulses of tetrade cane solutions into the nitrogen carrier gas. External sample loops having volumes of 50 microliters Were used. Each time that a valve Was opened, about 50 microliters of solution ?oWed into a 1/16" O. D., 0.040" I. D. nickel tube in Which the solution Was vaporiZed by heat from hot oil ?oWing over the outside of the tube. Nitrogen carrier gas moved the vapor from the small tube into the ALD reactor tube. Similar results Were obtained.

In another series of examples, pulses of those precursors that are liquids at room temperature Were delivered for ALD experiments similar to examples 2, 4, 6, 8 and 10 using 4-port sampling valves With small (0.5 microliter) internal sampling loops (Valco model EH2CI4WE.5PH, Valco Instruments, Houston, Tex.). Each time that a valve Was opened, about 0.5 microliters of liquid ?oWed into a 1/16" O. D., 0.040" I. D. nickel tube in Which the liquidWas vaporized by heat from hot oil ?oWing over the outside of the tube. Nitrogen carrier gas moved the vapor from the small tube into the ALD reactor tube. Similar results Were obtained.

Example 12


A hafnium oxide layer Was deposited using the apparatus of FIG. 1. Doses of 05x10“9 moles/cm2 of tetrakis(dimethy lamido)hafnium vapor and 4><10_9 moles/cm2 of Water vapor Were injected alternately every 5 seconds into a deposition chamber held at 2500 C. The chamber Was also fed a continu ous How of nitrogen carrier gas su?icient to maintain a pres sure of 0.15 Torr. The deposition chamber had a cross-sec tional area of 2.3 square centimeters in the plane perpendicular to the direction of gas ?oW through the cham ber. The outlet of the deposition chamber Was attached to a vacuum pump With capacity (195 liters/minute) su?icient to pump a volume equal to the deposition chamber in about 0.012 seconds. As a result of these reaction conditions, a transparent,

electrically insulating hafnium oxide ?lm Was deposited on substrates in the deposition chamber and onto its inner Walls. lts composition Was determined to be HfO2 by Rutherford backscattering spectroscopy (RBS) of a ?lm on a glassy car bon substrate. No carbon or nitrogen Was detected (<1 atomic percent). By ellipsometry, its thickness Was determined to be 0.1 nanometer/ cycle and its refractive index 2.05. Combining


US 8,334,016 B2 27

data from RBS and ellipsometry yielded a density of about 9. The thickness Was constant over the Whole deposition region, to Within the estimated measurement error of about 1%. Small-angle X-ray re?ectivity measurements con?rmed the thickness and gave a density of 9.23 g/cm3 . X-ray re?ectivity also shoWed that the ?lms are very smooth, With root mean square surface roughness about 0.4 nm for a ?lm 43 nm thick. Scanning electron microscopy shoWed that ?lms groWn at 150° C. are even smoother than the ones groWn at 250° C.

Repeating Example 12 With higher doses of either reactant did not increase the ?lm thickness or change its properties. These results shoW that the surface reactions are self-limiting. This conclusion Was con?rmed by placing inside the deposi tion chamber 110 a quartz crystal micro-balance (not shoWn), Which shoWed that the amount of mass deposited ?rst increased and then reached a plateau as the siZe of each dose Was increased. As a result of these self-limiting surface reac tions, uniform ?lms could be deposited inside holes With ratios of length to diameter over 50. Uniformity of thickness inside these holes Was improved by increasing the dose to 10 times the minimum required for saturation of the reactions on a ?at surface Without the holes. Reducing the capacity (speed) of the vacuum pump also helps to improve the step coverage by reducing the linear velocity of the vapors through the deposition chamber, thereby increasing the time during Which the vapors can diffuse doWn the holes, i.e. increasing the ?ux (Langmuirs of exposure). FIG. 3 shoWs a scanning micrograph of holes coated With hafnium oxide, cleaved to reveal their highly uniform thickness. The hafnium oxide layer is the bright line outlining each of the narrow vertical holes in the silicon, Which appears as a dark background. At the top of the micrograph is the upper surface of the silicon from Which the holes Were etched prior to the deposition of the hafnium oxide.

Repeating Example 12 With substrate temperatures in the range from 1000 C. to 300° C. gave similar results. At tem peratures above 300° C., the thickness increased With increas ing the dose of tetrakis(dimethylamido)hafnium. This shoWs that the surface reaction is not self-limiting at temperatures above 300° C., due to thermal decomposition of tetrakis(dim ethylamido)hafnium.

Example 13

ALD of Zirconium Oxide

Example 12 Was repeated With tetrakis(dimethylamido) Zirconium in place of tetrakis(dimethylamido)hafnium. Films of Zirconium dioxide With similar properties Were deposited.

Example 14


Example 12 Was repeated With tert-butanol vapor in place of Water vapor. Films of hafnium dioxide With similar prop erties Were deposited.

Example 15

ALD of Tantalum Oxide

Example 12 Was repeated With ethylimidotris(diethylami do)tantalum vapor in place of tetrakis(dimethylamido)

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28 hafnium vapor. Transparent ?lms of Ta2O5 Were deposited. They have a refractive index of 2.2, and a thickness of about 0.06 nm per cycle.

Example 16

ALD of Aluminum Phosphate

ALD Was carried out using altemating doses of 3x10“9 moles/cm2 of the vapors of trimethylaluminum and diisopro pylphosphate at a substrate temperature of 400° C. Transpar ent aluminum phosphate ?lms With approximate composition Al2P4Ol3 Were deposited at a rate of 0.1 nm per cycle. They had a refractive index of about 1.5.

Example 17


ALD Was carried out using altemating doses of 3x10“9 moles/cm2 of trimethylaluminum vapor and 1 2x10“8 moles/ cm2 of tris(tert-butoxy)silanol vapor at a substrate tempera ture of 300° C. Transparent aluminum silicate ?lms With approximate composition Al2Si8O 19 Were deposited at a remarkably high rate of 1 nm per cycle. They had a refractive index of about 1 .48. The surfaces of the ?lms are very smooth; atomic force microscopy determined a root mean square roughness of less than 0.8 nm for an aluminum silicate ?lm 150 nm thick. The tensile stress in a ?lm 2 micrometers thick on a silica substrate Was measured to be about 0.2 giga Pascals. A similar ?lm deposited on single-crystalline silicon shoWed a smaller tensile stress of 0.03 giga-Pascals. A ?lm 6 microns thick shoWed cracks and delamination because of the tensile stress.

This tensile stress can be reduced, eliminated, or even reversed to compressive stress by plasma treatment. The deposition is temporarily halted after a thin layer (such as 5 to 10 nm) has been deposited, a radio-frequency plasma (in a loW-pressure gas such as O2+argon) is applied, and then the plasma poWer is stopped and the deposition is resumed. Mul tiple cycles of deposition and plasma treatment may be used to build up thicker layers With tensile or compressive stress values adjusted to the requirements of particular applications, particularly those requiring thicker ?lms.

Example 18


ALD Was carried out using altemating doses of 3x10-9 moles/cm2 of trimethylaluminum vapor and 3x10“8 moles/ cm2 of tris(tert-butoxy)silanol vapor at a substrate tempera ture 200° C. Transparent aluminum silicate ?lms With approximate composition Al2Sil6O35 Were deposited at a remarkably high rate of 2 nm per cycle. They had a refractive index of about 1.47.

Example 19


ALD Was carried out With alternating doses of 3x10“9 moles/cm2 of tris(dimethylamino)aluminum vapor and 3x10“8 moles/cm2 of tris(tert-butoxy)silanol vapor at a sub strate temperature 250° C. An aluminum silicate ?lm Was formed With thickness 0.1 nm/cycle and a refractive index of about 1.46.


in the united states district court for the ......upon information and belief, defendant micron...

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