avs 2012 poster v3 (final version)

1
Interfacial properties of atomic layer deposited TiO 2 films on InAs (100) surfaces ALD of TiO 2 on etched InAs surfaces Conclusions Native oxide consumption is verified during ALD of TiO 2 on InAs (100) surfaces. In oxides “bubble” to surface of TiO 2 films during the deposition. Native oxide consumption rate increases as deposition temperature is raised during the deposition of TiO 2 on InAs (100) and GaAs (100) surfaces. NSF CAREER award (DMR-0846445) Materials and Devices for Information Technology (MDITR) STC (DMR-0120967) Dr. Karen Gaskell (UMD) for taking the XPS data ALD of TiO 2 on native oxide InAs surfaces Liwang Ye, Theodosia Gougousi Department of Physics , UMBC Practically sharp interface is obtained after the deposition of TiO 2 on HF and NH 4 OH etched InAs (100) surfaces The deposition of high-κ dielectrics on III-V semiconductors has been under intensive study due to its potential applications in metal-oxide-semiconductor field-effect transistors (MOSFET). The interface plays an important role in improving the performance of the semiconductor devices. Consumption of native oxides has been demonstrated for Atomic Layer Deposition (ALD) of metal oxides on III-V substrates when amide precursors are used. In this work we investigate the deposition and interfacial properties of TiO 2 on InAs. UMBC UMBC Temperature dependence of the native oxide consumption Starting surfaces: HF or NH 4 OH etched InAs (100) surfaces. Deposition Temperature: 200°C TiO 2 film thickness: ~2.2 nm Starting surfaces: Degreased native oxide InAs (100) surfaces. Deposition Temperature: 100~250°C Precursors: Tetrakis dimethyl amino titanium (TDMATi) and H 2 O Starting surfaces: Degreased native oxide InAs (100) surfaces Deposition temperature: 200°C Native oxides are consumed gradually. In oxides “bubble” to the surface of the TiO 2 films. 46 44 42 40 As-In AsO x As 2 O 3 As 2 O 5 As 3d 20 19 18 17 16 15 In 4d In-As In 2 O 3 In 2 O x 152 148 144 140 136 As 3p As 2 O 3 As 2 O 5 As-In AsO x 448 447 446 445 444 443 442 In-As In-O In 3d 5/2 Intensity Binding energy (eV) Starting surface 100°C 150°C 200°C 250°C ALD of ~2nm TiO 2 on InAs (100) surfaces ALD of ~3nm TiO 2 on InAs (100) surfaces Native oxide consumption rate increases as deposition temperature is raised. At 250°C As oxides are almost completely removed; some In oxide left. ~ 1.6 nm native oxide InAs epoxy TiO 2 ~4.3nm InAs epoxy Intensity starting surface after the deposition HRTEM of ~4.3nm TiO 2 on native oxide InAs (100) surfaces 448 447 446 445 444 443 In-As In-O In 3d 5/2 24 22 20 18 16 14 In 4d In-As In 2 O x In 2 O 3 O2s 45 40 35 30 As 3d As-In As 2 O 3 As 2 O 5 Ti 3p 152 148 144 140 136 As 3p As-In As 2 O 3 As 2 O 5 Starting surfaces ~2.0 nm TiO 2 ~3.7 nm TiO 2 ~6.4 nm TiO 2 ~3.0 nm TiO 2 ~6.4 nm TiO 2 Sputtered Intensity Binding energy (eV) Native oxide evolution during TiO 2 deposition Introduction Formation of a practically sharp interface is verified by HRTEM. Substrate Native oxide TiO 2 (a) (b) (c) (d) (a)Starting surface: native oxide covered InAs (100) surface (b)During the deposition: both As and In oxides are consumed gradually; In oxides diffuse gradually through the TiO 2 film and accumulate on its surface. (c)Interface is almost free of native oxides. Some In oxides remain on the topmost layer of the TiO 2 film. (d)Remaining surface In oxides are removed by sputtering. Starting surfaces: Degreased native oxide GaAs (100) surfaces Deposition temperature: 100~250°C ~2nm TiO 2 on GaAs ~3nm TiO 2 on GaAs ALD of TiO 2 on GaAs (100) surfaces Native oxide consumption rate increases as deposition temperature is raised. At 250°C As oxides are almost complete removed; some Ga oxide left. Acknowledgements 45 40 35 As 3d As 2 O 5 As 2 O 3 As-In Ti 3p 448 447 446 445 444 443 In-O In-As In 3d 5/2 24 22 20 18 16 14 In 4d In 2 O 3 In 2 O x In-As O 2s HF etched + 2.2 nm TiO 2 As received InAs (100) NH 4 OH etched + 2.2 nm TiO 2 Binding energy (eV) Intensity 152 148 144 140 136 As 3p As-In As 2 O 3 As 2 O 5 48 46 44 42 40 As 3d As 2 O 5 As 2 O 3 As-Ga AsO x 22 21 20 19 18 Ga-As Ga 2 O Ga 2 O 3 Ga 3d 46 44 42 40 As 3d As 2 O 5 As 2 O 3 AsO x As-Ga Intensity Binding energy (eV) 100°C 150°C 200°C 250°C 22 21 20 19 18 Ga-As Ga 2 O Ga 2 O 3 Ga 3d Starting surface 46 44 42 40 As 2 O 5 As 2 O 3 AsO x As-In As 3d 152 148 144 140 136 As 3p As 2 O 5 As 2 O 3 As-In AsO x 447 446 445 444 443 442 In-As In-O In 3d 5/2 20 19 18 17 16 15 In 4d In 2 O 3 In 2 O x In-As Binding energy (eV) 100°C 150°C 200°C 250°C Starting surface

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Page 1: AVS 2012 Poster v3 (final version)

Interfacial properties of atomic layer deposited TiO2 films on InAs (100) surfaces

ALD of TiO2 on etched InAs surfaces

Conclusions

Native oxide consumption is verified during ALD of TiO2 on InAs (100)

surfaces.

In oxides “bubble” to surface of TiO2 films during the deposition.

Native oxide consumption rate increases as deposition temperature is

raised during the deposition of TiO2 on InAs (100) and GaAs (100)

surfaces.

NSF CAREER award (DMR-0846445)

Materials and Devices for Information Technology (MDITR) STC

(DMR-0120967)

Dr. Karen Gaskell (UMD) for taking the XPS data

ALD of TiO2 on native oxide InAs surfaces

Liwang Ye, Theodosia Gougousi Department of Physics , UMBC

Practically sharp interface is obtained after the deposition of TiO2 on HF

and NH4OH etched InAs (100) surfaces

The deposition of high-κ dielectrics on III-V semiconductors has been under intensive

study due to its potential applications in metal-oxide-semiconductor field-effect

transistors (MOSFET). The interface plays an important role in improving the

performance of the semiconductor devices. Consumption of native oxides has been

demonstrated for Atomic Layer Deposition (ALD) of metal oxides on III-V substrates

when amide precursors are used. In this work we investigate the deposition and

interfacial properties of TiO2 on InAs.

UMBC UMBC

Temperature dependence of the

native oxide consumption

Starting surfaces: HF or NH4OH etched InAs (100) surfaces.

Deposition Temperature: 200°C

TiO2 film thickness: ~2.2 nm

Starting surfaces: Degreased native oxide InAs (100) surfaces.

Deposition Temperature: 100~250°C

Precursors: Tetrakis dimethyl amino titanium (TDMATi) and H2O

Starting surfaces: Degreased native oxide InAs (100) surfaces

Deposition temperature: 200°C

Native oxides are consumed gradually.

In oxides “bubble” to the surface of the TiO2 films.

46 44 42 40

As-In

AsOx

As2O3As2O5

As 3d

20 19 18 17 16 15

In 4d

In-AsIn2O3

In2Ox

152 148 144 140 136

As 3p

As2O3

As2O5

As-In

AsOx

448 447 446 445 444 443 442

In-As

In-O

In 3d5/2

Inte

ns

ity

Binding energy (eV)

Starting

surface

100°C

150°C

200°C

250°C

ALD of ~2nm TiO2 on InAs (100) surfaces

ALD of ~3nm TiO2 on InAs (100) surfaces

Native oxide consumption rate increases as deposition temperature is

raised.

At 250°C As oxides are almost completely removed; some In oxide left.

~ 1.6 nm

native oxide

InAs

epoxy

TiO2 ~4.3nm

InAs

epoxy

Inte

nsit

y

starting surface after the deposition

HRTEM of ~4.3nm TiO2 on native oxide InAs (100) surfaces

448 447 446 445 444 443

In-AsIn-O

In 3d5/2

24 22 20 18 16 14

In 4d

In-AsIn2OxIn2O3

O2s

45 40 35 30

As 3d

As-InAs2O3As2O5

Ti 3p

152 148 144 140 136

As 3p

As-InAs2O3

As2O5

Sta

rting

su

rfac

es

~

2.0

nm

TiO

2

~3.7

nm

TiO

2

~6.4

nm

TiO

2

~3.0

nm

TiO

2

~6.4

nm

TiO

2

Sp

utte

red

Inte

ns

ity

Binding energy (eV)

Native oxide evolution during TiO2 deposition

Introduction

Formation of a practically sharp interface is verified by HRTEM.

Substrate

Native oxide

TiO2

(a) (b) (c) (d)

(a)Starting surface: native oxide covered InAs (100) surface

(b)During the deposition: both As and In oxides are consumed gradually;

In oxides diffuse gradually through the TiO2 film and accumulate on its

surface.

(c) Interface is almost free of native oxides. Some In oxides remain on

the topmost layer of the TiO2 film.

(d)Remaining surface In oxides are removed by sputtering.

Starting surfaces: Degreased native oxide GaAs (100) surfaces

Deposition temperature: 100~250°C

~2nm TiO2 on GaAs ~3nm TiO2 on GaAs

ALD of TiO2 on GaAs (100) surfaces

Native oxide consumption rate increases as deposition temperature is

raised.

At 250°C As oxides are almost complete removed; some Ga oxide left.

Acknowledgements

45 40 35

As 3d

As2O5

As2O3

As-In

Ti 3p

448 447 446 445 444 443

In-O

In-As

In 3d5/2

24 22 20 18 16 14

In 4d

In2O3

In2Ox

In-As

O 2s

HF

etc

he

d

+ 2

.2 n

m T

iO2

As

rec

eiv

ed

InA

s (1

00

) N

H4 O

H e

tch

ed

+ 2

.2 n

m T

iO2

Binding energy (eV)

Inte

nsit

y

152 148 144 140 136

As 3p

As-InAs2O3

As2O5

48 46 44 42 40

As 3d

As2O5As2O3

As-Ga

AsOx

22 21 20 19 18

Ga-AsGa2O

Ga2O3

Ga 3d

46 44 42 40

As 3d

As2O5 As2O3AsOx

As-Ga

Inte

ns

ity

Binding energy (eV)

100°C

150°C

200°C

250°C

22 21 20 19 18

Ga-AsGa2OGa2O3

Ga 3d

Starting

surface

46 44 42 40

As2O5As2O3

AsOx

As-In

As 3d

152 148 144 140 136

As 3p

As2O5

As2O3As-In

AsOx

447 446 445 444 443 442

In-AsIn-O

In 3d5/2

20 19 18 17 16 15

In 4d

In2O3

In2Ox

In-As

Binding energy (eV)

100°C

150°C

200°C

250°C

Starting

surface