Oxide Films & Nanostructures on Silicon

Oxide Films & Nanostructures on Silicon for Thermal Energy Harvesting in

Microelectronic Devices

R. BacheletR. Moalla, A. Carretero-Genevrier, L. Mazet, L. Louahadj, J. Penuelas, B. Vilquin, C. Dubourdieu, G. Saint-Gironsq

Institut des Nanotechnologies de Lyon UMR CNRS 5270 http://inl.cnrs.fr

R. Bachelet – GDR Thermoélectricité – Nancy 9-10 décembre 2013

Outline

I. Intro: Context & INL presentation p

II Thi fil t d d S TiOII. Thin films: n-type doped SrTiO3

III Nanowires: Hollandites (BaMn O )III. Nanowires: Hollandites (BaMn8O16)

IV. Pyroelectric epitaxial thin films…y p

IV C l iIV. Conclusions



Context: nanostructured materials for TEG J Snyder et al Nat Mat 7 105 (2008)G.J. Snyder et al., Nat. Mat. 7, 105 (2008)

C.J. Vineis et al., Adv. Mat. 22, 3970 (2010)K. Koumoto et al., J. Am. Ceram. Soc. 96, 1 (2013)

Material challenges/requirements:

ZT = S2 T / (Ke+Kl) ZT > 1

• Semi-conductor materials => large , S

• Nanostructured => Decrease LNanostructured > Decrease L

• Efficiency / Reliability (oxidation/intermixing…)

• Non toxic / Abundant elementsNon toxic / Abundant elements

• Integration…



Scientific and application fields250 people

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InformationEnergy

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500 m2 clean room

Informationtechnologies HeteroHetero and and NanoNano--structuresstructures

S lS l llll

NanophotonicsNanophotonics

PhotonicsPhotonicsPhotovoltaicsPhotovoltaics

FunctionnalFunctionnalmaterialsmaterialsNanomaterialsNanomaterials

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BiotechnologiesBiotechnologiesHealthHealth

ElectronicsElectronics

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NanodevicesNanodevices

LabsLabs--onon--aa--chipchip

HealthHealthLife science/health care

TechnologiesHeterogeneousHeterogeneous designdesign

BiochipsBiochips

SensorsSensors

MEMSMEMS--NEMSNEMS



Technologies

NANOLYON technological platform

A « proximity » platform for Micro & Nano TechnologiesA « proximity » platform for Micro- & Nano-Technologies

To develop novelp(nano)materials

& novel concepts of devices

& characterizations& characterizations

New clean roomsin 2013(500 2)(500 m2)

MBESputteringSputtering

Sol-gelLithography

…



Semiconductor nanostructures: reducing dimensions at the nanoscale

III-V NanostructuresSemiconductor nanostructures: reducing dimensions at the nanoscale…

2D: SLs & QWs 1D: NWs InP

200 nmInAlAsP

0D: QDs0D: QDs



Works led by P. Regreny and Michel Gendry, H&N team, INL

Oxide Films and Nanostructures /Si

1. Thin films: n-type doped SrTiO3

2. Nanowires: Hollandites (BaMn8O16) BaMn8O16( 8 16)

Si (Substrat)10 µm

3 Pyroelectric epitaxial thin films

Si (Substrat)10 µm

3. Pyroelectric epitaxial thin films…



1. n-type doped SrTiO3 /SiSrTiO3: a model for oxide electronics • Doped by aliovalent cationsSrTiO3: a model for oxide electronics

Tuning (& S)By doping

La-STO:(La[3+] Sr[2+])TiO3

Doped by aliovalent cations

• Doped by oxygen vacancies:

(La[ ],Sr[ ])TiO3

p y yg

T = 300 K



G. Herranz et al. PRL 98, 216803 (2007)B. Jalan & S. Stemmer, APL 97, 042106 (2010)

1. n-type doped SrTiO3 /SiI i i t f t th lIncreasing interfaces at the nanoscale

• Superlattices • (Nano)Polycrystalline

Nb-STO: Sr(Ti[4+],Nb[5+])O3

ZT300K > 1 with Kmin 1.4 W.m-1.K-1

minSbulk = 61 V.K-1; n = 2-4 1021 cm-3 ; nundoped < 1015 cm-3



H. Ohta et al., Nat. Mat. 6, 129 (2007)S. Ohta et al., APL 87, 092108 (2005)

K. Koumoto et al., J. Am. Ceram. Soc. 96, 1 (2013)

1. n-type doped SrTiO3 /Si

Epitaxial SrTiO3/Si… 14 ML

STO(110)1000

Doped by oxygen vacancies

STO(110)

(a) 100 W

100

1000

cps)

SrTiO3-

.)

(b) 200 W

20 30 40 50 60 70

10

Int.

(c

nsity

(a.u

.

(c) 300 W

20 30 40 50 60 70

2 (°)

Inte

(d) 400 W SrTiO

0 34 0 35 0 36 0 37 0 38

SrTiO3



0,34 0,35 0,36 0,37 0,38

q// (Å-1)G. Niu et al. APL 2009 L. Louahadj et al.

1. n-type doped SrTiO3 /Si

Superlattices and 2DEGsLAO/STO SL

Electrical measurements (I-V) on p-type Si(001):> j ti

LaAlO3

S TiO

LAO/STO SLs=> p-n junction

TE measurements: in progress SrTiO3

LaAlO3

SrTiO3

TE measurements: in progress(, S, K)Collab: Fransisco Rivadulla (CIQUS, Spain)(Univ Santiago de Compostela)(Univ. Santiago de Compostela)

Perspectives:4 nmO. Marty ‐ INL(UCBL)

C. Merckling et al.

Perspectives:- Full TE measures- SL polycristalline - doped / undoped…- p-type thin films gp yp



2. Oxide Nanowires of HollanditesIntegration of 1D oxide nanowires in confined geometries (CSD)

1. Synthesis: track-etched polymer template assisted elaboration

Integration of 1D oxide nanowires in confined geometries (CSD)

1. Synthesis: track etched polymer template assisted elaboration

P700‐1000°C

Pore size from 10 nmPrecursor solution (sol‐gel)

SiliSilicon

A. Carretero-Genevrier et al.,



Chem. Soc. Rev. (2013)

2. Oxide Nanowires of Hollandites

2. Some results

A Carretero Genevrier et al Chem Soc Rev (2013)S300K = 20 μV/KPF = 30 W/cm K2



A. Carretero-Genevrier et al., Chem. Soc. Rev. (2013)Chem. Mater (2013)

PF75K= 30 W/cm.Kn=1022 cm‐3

Phys.Rev. B 79 085207 (2009

2. Oxide Nanowires of Hollandites

3. Perspectives

• Measuring TE parameters

• Composite materials (NWs + SC Matrix)

• n- & p-type materials… p yp

• Integration in modules (structuring, contacts,…)



3. Pyroelectric epitaxial thin films

• Thermal energy harvesting for electrical conversion

With Thermoelectrics

I = f (T)

Electrode

(b) Pt

Electrode

PE

ElectrodePs

BSTPZTPMN‐PT

SROLa‐STOLNO

With Pyroelectrics

I = f (dT/dt)

Si(001)

BufferLNO

STO

SiSOIGaAs

I f (dT/dt)



3. Pyroelectric epitaxial thin films(b) Pt

PPE

Electrode

Ps

(b) Pt

BSTPZTPMN‐PT

SROP

Si(001)

Buffer

Electrode

SROLa‐STOLNO

STO

Si( )SOIGaAs

Polycristalline Single crystallinePolycristalline Single-crystalline

Bulk materials ref +Thin films + ++?Thin films + ++?

>1 mW/cm3 for temperature variations of 10°C 1 mW/cm for temperature variations of 10 C PhD thesis starting (R. Moalla): Collab. with LGEF-INSA (G. Sebald, D. Guyomar)

S B Lang Phys Today 58 31 (2005)



S.B. Lang, Phys. Today 58, 31 (2005)G. Sebald et al., Smart Mater. Struct. 18, 125006 (2009)

3. Pyroelectric epitaxial thin filmsFerroelectric ABO3/SrTiO3/SiFerroelectric ABO3/SrTiO3/Si…

P

PFM (Collab. B. Gautier, INL):

P

In progress:L Mazet et alL. Mazet et al.R. Moalla et al.

Material challenge:- High Pyroelectric coef.High Pyroelectric coef.- High P - Out-of-plane P- Low leakage currents

S. Yin et al., Thin Solid Films 520, 4572 (2012)G. Niu et al., Thin Sol. Films 520, 4595 (2012)

g

=> BST, PZT, PMN-PT



, , ( )G. Niu et al., Microelec. Eng. 88, 1232 (2011) BST/SRO/STO/Si

Conclusions

• SrTiO3-based TE thin films by physical method3control of , S by doping & reducing KL by nanostructuring

H ll dit N i b i i l h i l th d• Hollandites Nanowires by original chemical methodcontrol of density, diameter, chemical composition..

• Need of full TE characterizations…

• Alternatively, promising single-crystalline Pyroelectric films



Oxide Films & Nanostructures on Silicon

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