2010 kiev arw nato bondarenko

8/8/2019 2010 Kiev ARW NATO Bondarenko

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This is invited talk presentedby Vitaly Bondarenko at

1st Ukrainian-French SeminarSemiconductor-on-Insulator Materials,

Devices and Circuits: Physics,Technology and Diagnostics and6th International SemOI Workshop

Nanoscaled Semiconductor-on-Insulator

Materials, Sensors and Devices25-28 September, 2010

Cultural Center Jerelo, Kyiv, Ukraine


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ZnO films and nanocrystalson bulk silicon and SOI wafers:Formation, Properties and Applications

V. Bondarenko, E. Chubenko

Belarusian State Universityof Informatics andRadioelectronics,

Minsk, Belarus

A. Belous, V. Malyshev

Technical CentreBelmicrosystems,

Integral Corporation,Minsk, Belarus

M. Balucani

Rome University La Sapienza,Rome, Italy


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Content

Introduction

- What is ZnO- Industrial ZnO Applications- ZnO in Electronics: Technologies- ZnO in Electronics: Applications- ZnO vs Si and others: Properties- ZnO vs Si: Applications and Technological Issues

Integration of ZnO with Si substrates- Motivation- Technological requirements- Possible solutions for ZnO & Si integration

Low temperature ZnO deposition- Electrochemical

- Hydrothermal

Applications Conclusions


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What is Zinc Oxide ?

Zinc oxide is an inorganic compoundwith the formula ZnO.

It usually appears as a white powder,nearly insoluble in water.

It is one of the so-called II-VI semiconductors, andhas wide direct band gap

In nature ZnO occurs as the mineralZincite

http://en.wikipedia.org/wiki/Zinc oxide

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Industrial ZnO Applications

Total world production of ZnO:105 tones

< 0,1 %

Total world production of silicon:6106 tones

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ZnO in Electronics: Technology

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ZnO in Electronics: Applications

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Parameter (300 K) Si GaAs ZnO GaN -SiC

Eg, eV1,12

indirect

1,42

direct

3,35

direct

3,45

direct

3,05

direct

Luminescenceefficiency, %

10-4 60-70 70 70-80 -

Electron / Hole Hallmobility, cm2/(Vs)

1600 /430

8500 /400

300 / 10 500 / 150 900 / 40

Crystal lattice cubic cubic hex hex hex

Lattice constants0 and 0,

5,43 5,653 3,245,21

3,195,19

3,0715,11

Thermal expansioncoefficient, umm1K1

2,6 5,76,51

3,02

3,17

5,59

4,3

4,7

Thermal conductivity,W/(cmK) 1,49 0,55 0,60 2 4,9

ZnO vs Si and others

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ZnO vs Si: Applications and Technological Issues

Integrated circuitry- MOS- CMOS- BipolarHighSpeedHighDensityHighReliabilityNoLEDs

NoPiezo

OptoelectronicsPiezoeffect based devicesSAW DevicesNo Integrated circuitry

Silicon Zinc Oxide

ZnO (25 mm) $ 3500

Si (100 mm) $ 15Si SOI (150 mm) $ 300

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Integration of ZnO with Si substrates: Motivation

ZnO devices and Si devices integrated on a single die We can use the Si fab to fabricate ZnO devices Lower cost of the ZnO devices

ZnO

ZnO

Si

Processing

Si

SiDicing

SOI bulk Si

Direct integration

Hybrid Integration

Discrete Devices

Packaging

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and as a result

Major Problem

Genesis of Defects in Heterostructures

CRACK!

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Integration: Marriage of ZnO with Si

What we do know: Marriage is result of love(not always but ....)

Does Si love ZnO ? No !(Si wafer is thick, ZnO layer is thin)

Does ZnO love Si ? - Yes !(ZnO layer is thin, Si wafer is thick. It is very

convinient to live on the thick substrate)


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Integration: Marriage of ZnO with Si

What to do ?Lets introduce buffer layer between partners !!!

What about childrens ??? (We will see !!!)

Porous silicon (PS) as a buffer layer

reducing mismatch stress

increasing adhesion


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How to do it, if we know what to do ?

E.B. Chubenko, V.P. Bondarenko, M. Balucani, Tech. Phys. Lett. 35 (2009) 1160.

PS with metal sublayerPS

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Local Low T Deposition:- electrochemical- hydrothermal

Thermal Budget Issue: When to deposit ZnO ?

~ 700technological steps

Hence:T


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Electrochemical deposition of ZnO on Si

ZnO can be electrochemically deposited from aqueoussolution at low temperature (T = 80C)

BUT:Porous silicon buffer layer due to its huge effective surface is easily

etched in hot water (T > 50C) solution with pH > 6

How to solve the problem of PS etching: protect porous silicon with thin metal layer deposit ZnO from non aqueous solution

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Realization: Equipment

100 mm Si waferwith

ZnO layer

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Realization: Solutions & Regimes

Solutions for ZnO depositionAqueous:

Base Pure water

Components 0.05 0.1 M of Zn(NO3)2

Deposition velocity 1 1.5 microns/min

Current density 2 10 mA/cm2

Temperature 60 85C

Non aqueous:

Base DMSO

Components 0.03 M of ZnCl

0.1 M of KCl (for good conductivity)

Deposition velocity 0.1 0.2 microns/min

Current density 0.3 0.5 mA/cm2

Temperature 95 100C

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Realization: Local Deposition of ZnO

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Electrochemical deposition of ZnOfrom aqueous solution

E.B. Chubenko, V.P. Bondarenko, M. Balucani, Tech. Phys. Lett. 35 (2009) 1160., J. Cembrero, D. Busquets-Mataix, Thin Solid Films 517 (2009) 2859.

current density

Depending on process parameters:current density, temperature, time, concentration,different ZnO morphology types can be obtained

continuousporousprismaticneedle-like

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ZnO deposition on metal buffer layer (aqueous)

Deposition potential

Current density

Voltammograms

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ZnO deposition on metal buffer layer

j = 2,5 /2

j = 5 /2

j = 7,5 /2

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Z O d iti PS b ff l f page 21/37


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ZnO deposition on PS buffer layer fromnon-aqueous solution)

Cross section Top viewTime

min

0

25

45

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ZnO photoluminescence

Electrochemically deposited ZnO showsyellow band photoluminescence

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Hydrothermal ZnO deposition on Si

HMTA hexamethylenetetramine

Film of prisms Prismatic columns Rosettes

Depending of temperature and solutioncomposition various structures can beobtained

75 C 85 C 95 C

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Hydrothermal deposition of ZnO on seed layer

Hydrothermally grown ZnO rods shows emissions inboth UV and visible range,

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PS buffer layer with different thickness H

ZnO seed layer was electrochemically deposited

H = 1 m H = 4 m H = 6 m

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H = 1 m H = 4 m H = 6 m

Same sampleses after hydrothermal treatment inZn(NO3)2 + HMTA solution at 85 C

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ZnO deposition into porous alumina oxide

1 m

Al sputtering

Al anodization

ZnO deposition

Ti

Ni

Al2O3

ZnO

Si

TiO2

surface cross-section

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Possible Applications of ZnO grown on PS

Photodetectors

Photovoltaic cells (solar cells)

Betta-voltaic cells Gas sensors

Others (scintillation counter, piezo

energy generators, nanomechanics)

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Photodetectors: ZnO/PS heterojunction

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ZnO is transparent conductive material

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Cu

rrent/mA

Voltage / V

Photovoltaic cells: ZnO/Si heterojunction

p g

Z O f b t lt ipage 34/37


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ZnO for beta voltaicbatteries

pincell

Electron beam current / A

Shortcircuitc

urrent/A

Principle of Operation

p g

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Chemical gas sensors

Porous ZnO film surface

p g

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Others

Piezoenergy generators Expected characteristics:Voltage up to 20 mV

Current up to 1 A

Scintillationcounter

High performanceLongevityHigh stopping powerWide luminescence range

(compatible with Si)

p g

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BoltHead

BoltRod

Nanoscrews for Nanomechanics Nanolamps

ZnO crystalls grown on low porosity PS

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http://ru.wikipedia.org/wiki/%D0%A4%D0%B0%D0%B9%D0%BB:Gluehlampe_01_KMJ.jpg


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As a conclusion: Problems to be solved

Development of the p-type ZnO doping techniques

Improvement of crystalline structure of electrochemicallydeposited ZnO

Improvements of the ZnO deposition process into PAAO matrix

Acknowledgements

This work has been funded by the Belarussian Foundationfor Basic Research under the Project 06-3029 and

by the Rice Technology S.r.l. (Italy)

2010 kiev arw nato bondarenko

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