piezomaterials @leti piezo background by pierre and … · 2019. 7. 5. · guillaume...

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Process capability

Piezo background

PIEZOMATERIALS @LETI

Material trends

Piezoelectric effect was first proven in 1880

by Pierre and Jacques Curie

Guillaume [email protected] l Prototyping Pilot Line Workshop l Friday, June 28th 2019

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INTRODUCTION MEMS AT LETI

CEA-LETI : A LEADING MEMS R&D LAB WORKING FOR INDUSTRY

30 YEARS BACKGROUND IN MEMS

200 PEOPLE involved in MEMS (sensors, actuators, RF, packaging, process, characterization, IC design)

COMPLETE 200MM PILOT LINE FOR M&NEMS MANUFACTURING

330 PATENTS PORTOFOLIO IN THE MEMS FIELD

35 NEW PATENTS AND 100 PUBLICATION PER YEAR

Guillaume Rodriguez l Prototyping Pilot Line Workshop l Friday, June 28th 2019

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Piezo

stack

ACTUATORS

SENSORS

OPTICAL MEMS

HAPTICS

RF FILTERS

FLUIDIC BIO

pMUT

ENERGY HARVESTING

Micro-pump and

biological cells

manipulation

Varifocal Lens

Pyroelectric sensor

PZT and AlN actuation

Micro-miror

Solid Mounted Resonator

PIEZOMEMS

Guillaume Rodriguez l Prototyping Pilot Line Workshop l Friday, June 28th 2019Guillaume Rodriguez l Prototyping Pilot Line Workshop l Friday, June 28th 2019

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FROM MATERIAL DEPOSITION TO SYSTEM INTEGRATION

Characterizations

Prototyping

3D assembly

MEMS Fabrication

Electronic design

LETI covers the wholechain of development

Packaging

MEMS Design

New materials deposition

Process Integration

Material Nano-Characterization


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SENSING

3 MAIN PIEZO FAMILIES AT LETI

State of the art Solgel PZT properties

Several PZT device demonstrations : variable focus lens, micro-pump, optical scanner

2 Technological Transfers to and to a World-Class Foundry

Variable focus lens

Optical scanner

Sol-gel PZT Technology

7 years of industrial development with high maturity process, reliability, throughput…

Several AlN device demonstrations: BAW filter, High-SNR µphone, haptic sensor

Technological Transfer to a World-Class Foundry

PVD AlN Technology

AlN-on-glass for haptic

High-SNR microphone

Smart-cut crystal transfert

Strong collaboration with Soitec

Smart-cut LiNbO3 Technology

ACTUATING ACOUSTIC

SMR Filters

High electromechanical coupling

Kt2=26%


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TOOL SET

PZT PROCESS @LETI

Successfully transferred to 2 main foundries

SOL-GEL DepositionLead zirconium titanate

APPLICATIONS

LETI STRENGHT

A generic 200mm piezo test vehiculeON GOING DEVELOPMENT

MEMS actuatorsHigh K, High piezo coef

Properties

Piezo-ferro-electric

High piezo coefficient

High Pyro coeff

High K

Variable focus lens Micro-pump Optical scanning

Replace PZT by a Lead-Free piezo

A major challenge


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Improve crystallinity :

Smart interface

MOCVD AlN

Doped AlN :

Co-sputtering and conventional sputtering

Composition screening, versatile

AlN PROCESS @LETI

TOOL SET PVD DepositionAluminium Nitride

APPLICATIONS

LETI STRENGHT ON GOING DEVELOPMENT

NEMS sensors, Acoustic Wave Devices

Properties Sigma fxp

Thickness 200nm to 10µm

Thickness NU% < 0,5%@1σ

FWHM [002] < 1,5°

Dielectric constant = 10-11

Dielectric losses <0,1%

e31,f 1 C/m2

d31,f -2,5 pm/V

SMR Filters µCantilever Membranes

High maturity process, reliability, throughput on AlN process

Co-sputtering capability MSQ module : AlN doped

EVATEC ClusterlineTMSPTS Sigma® fxP


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TOOL SET APPLICATIONS

LETI STRENGHT ON GOING DEVELOPMENT

Reinhardt et al., IUS 2014

1st demo of a sub-micron-thick single-crystal FBAR

k² = 39.2 % and Q = 250 @ 2.5 – 3 GHZ

Q-factor still limited and Strong temperature dependence

Smart-cut approach

Direct deposition approachMOCVD national research program

Sputtering trials

PLD investment @Leti

Strong background in RF Filters

Strong background in BONDING

Collaborations with key players

LNO / LTO PROCESS @LETI

NEW

100mm to 200mm

5G challenges

Acoustic Wave DevicesSmart-cut Process

Overcoming limitations of wafer thinning

switch to Smart CutTM

What can offer this approach ?

High crystal quality at low thickness

But strong challenges

Learning curve on acoustic optimizations

(Q-factors, parasitics, T°C compensation)

Courtesy Solmates

Kt2 AlN = 6,5%

Kt2 LiNbO3 = 45%

XRD pattern : no significant crystal difference is noticed

between the lattice structure of the transferred LiTaO3

Gorisse et al , 2018 IEEE International Ultrasonics Symposium (IUS)


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to measure MEMS deflection under applied voltage and extract piezo coefficient d31

Wyko interferometer

Laser interferometryto measure e31 piezo coefficient

aix4PB system

Automatic 8’’probers for electrical characterization

C(V)Permittivity and dielectric losses P(V) Ferroelectric polarization I(V) leakage current and breakdown voltage

Wafer level electro-mechanical displacements analysis

Electrical characterization

MATERIALS AND DEVICES CHARACTERIZATION

X-Ray Diffraction Optical profilometry WDXRF spectrometer

3D scan & Local stress Composition and film thicknessstructural characterization

In line piezo layer metrology

8 inch wafer Double Beam

Laser Interferometer

Effective piezo coeficient d33,f

Fast measurement


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• Thin film piezoelectric material & technology knowledge

• High maturity processes, improvements done on reliability, repeatability, throughput…

• Background on process but also on design

• Broad range of deposition and characterization tools

• Investissement in emerging PLD technology and piezo coef characterization

• On-going research on RF filters

• To overcome limitations of standard AlN

• Higher bandwidth, higher frequencies

• With enhanced AlN (crystal, doped) or new piezo materials (LNO)

• New challenges for PIEZOMEMS

• Lead free materials (KNN, BCTZ,…)

• Transparent piezo stack for haptic

CONCLUSION


Leti, technology research institute

Commissariat à l’énergie atomique et aux énergies alternatives

Minatec Campus | 17 rue des Martyrs | 38054 Grenoble Cedex | France

www.leti-cea.com

Leti l 2018-09

Thank you for your attention

[email protected]

Contributors for the presentation- A. Lefevre

- G. Le Rhun

- F. Servant

- C. Billard

mailto:[email protected]

piezomaterials @leti piezo background by pierre and … · 2019. 7. 5. · guillaume...

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