JSI Bio-Nano-Space-12-03 - 2008 Jožef Stefan Institute Jamova 39 1000 Ljubljana Slovenija [email protected] Ferroelectrics: Towards Smaller Dimensions

Bio-Nano-Space-12-03 -2008

JSI

Jožef Stefan InstituteJamova 39

1000 LjubljanaSlovenija

[email protected]

Ferroelectrics: Towards Smaller Dimensionsand Complex Structure

Marija Kosec


JSI

Electronic Ceramics Department, K-5Head: Prof. Dr. Marija Kosec Staff: 20: 5 PhD, 4 Post-doc, 8 PhD students, 2 ing, 1 technician + part–time:

Research Activities Materials: Piezoelectrics:Pb(Zr,Ti)O3 (PZT), Relaksors: Pb (Mg1/3Nb2/3)O3 - PbTiO3 (PMN-PT), Lead free piezoelectrics:(K,Na)NbO3 (KNN), Tunable ferroelectrics: (Ba, Sr)TiO3 K(Nb,Ta)O3, Dielectrics: CuCa3Ti4O12 (CCTO) Oxide conductors: (La,Sr)CoO3 (LSCO), La-ruthenates, Multiferoic: BiFeO3 ( BaO, PbO), LaMnO3, ZnO


JSI

Processing: How to get extrem: properties, design, size….

Nano-powders:

sol-gel synthesis (PZT)mechanically activated synthesis (PMN-PT, KNbO3, NaNbO3,KNN)

Thin films by Chemical Solution Deposition (CSD)(PZT, PMN-PT, KNN, KNT, BST,CCTO)

Thick film:Screen printing (PZT, PMN-PT, KNN)Electrophoresis (PZT)Ink-jet printing (ZnO)

Bulk (KNN), Single crystal: KNN

Devices: C-MEMS

Medical transducersPressure sensors


JSI

A

B

OA

B

O

A: PbB: Ti,Zr

Polar structur,Electric dipols

Ferroelectric ceramic materials

Ec

Pr

P (C/cm2)

E (V/m)

0

S

(10-3

)

E (kV/cm)

-200 -150 -100 -50 0 50 100 150 200

0.18

0.20

0.22

0.24

0.26

0.28

0.30

700oC

C (

pF

)

U (V)

900oC

Ferroelectric anddielectric

Piezoelectric

Tunable


JSI

BaTiO3

PbTiO3 (PT)

Pb(Zr,Ti)O3 (PZT), (Pb,La)(Zr,Ti)O3 (PLZT)

Pb(Mg1/3Nb2/3)O3 (PMN)

Pb(Mg1/3Nb2/3)O3 – PbTiO3 (PMN-PT)

Pb(Zn1/3Nb2/3)O3 – PbTiO3 (PZN-PT), (PMN-PZN-PT)

PbSc1/2Ta 1/2 O3

high lead content (~60w%) ecological problems

Since last ten years: searching for lead free materials

A

B

OFeroelectric ceramics: CompositionFeroelectric ceramics: Composition


JSIlead-free ferroelectric materials:

Sodium potassium niobate (K,Na)NbO3 s.s. (KNN).

The best piezoelectric response for the compositions close to the MPB:KNN50/50

KNbO3-NaNbO3 phase diagram

TD tan d33(pC/N) kp kt

KNN 4.2 94.4 450 0.06 70 0.25 0.4

KNN-Sr 4.2 96.0 500 0.04 90 0.27 0.5

PbNb2O6 5.6 220 0.02 100 0.34

B.Malič, J.Bernard, J.Holc, D.Jenko, M.Kosec, J.Eur.Cer.Soc.,(2005) 2707


JSI

Cross-section SEM of 32Mbit NFRAM,from: H.S.Joo, Integr. Ferroel., 48(2002), 119.

Courtesy of Ferroperm Piezoceramics S/A

Bulk: mm, cm range

100 nm

Thin films < 1m Thick films >1m

100 nm

Ferroelectrics: Towards Smaller Dimensionsand Complex Structure


JSI

Thick film processing

crytical

PbO+ZrO2+TiO2 Pb(Zr,Ti)O3)

powder synthesis:

Shaping

Firing

Thick film

Tem.

Thick films >1m

Chem.reactions

clamping


JSI

Powder synth.

shaping

firing

thick film

Thick film procesing

screen printing ink jet printing electrophoretic deposition

Squeegee

Paste

Mask

Substrate

Screen


JSI

modeling

0,0E+00

5,0E-06

1,0E-05

1,5E-05

2,0E-05

2,5E-05

3,0E-05

0,0E+00 5,0E+03 1,0E+04 1,5E+04

Pressure [Pa]

Max

imum

def

lect

ion

[m]

Bridge

Cantilever

Diaphragm

Linear(Bridge)Linear(Cantilever)Linear(Diaphragm)

1

2

3

1

23

Marina Santo

Fibre optic cablecontroller

Opto-electronic

V

A

B

head

Optical sensor


JSI

Microstructure after firing 1h 850oC.

LTCC/PZT barriere/Au/PZT/Au

LTCC/Au/PZT/ Au


JSI

displacement

200V=3µm

dimensions 12.0 × 4.0 × 0.22 mm - 40µm thick PZT


JSI

Cross-section SEM of 32Mbit NFRAM,from: H.S.Joo, Integr. Ferroel., 48(2002), 119.

Courtesy of Ferroperm Piezoceramics S/A

Bulk: mm, cm range

100 nm

Thin films < 1m Thick films >1m

100 nm


JSI

dense, amorphous film

Drying, 200 C

Pyrolysis, 350 C

Crystallization, 600 C

Solution- precursor:Pb,Zr,Ti

Spinnig

wet film

dry film

dense, crystalline film

substrate

substrate

substrate

substrate

Synthesis

Chemical Solution Deposition (CSD) of Pb(Zr,Ti)O3

PZT


JSI

2-methoxyethanol method

Pb(OAc)2+x Zr(O R)4 +(1-x) Ti(O R)4

+

CH3-O-C2H4-OH

Reflux

destilation

PZT-solution (sol)

spinning Pt/Si –substrat

drying@ 200oC

pyrolysis@ 350oC

crystallization@ 600oC

PZT thin film

CH3-O-C2H4-OH

Budd, Dey, Payne , 1985

Turova, Turevskaya, Kessler, Yanovskaya, 2002.

O CH2

O CH2

M

R

n-1(RO)

Synthesis of PZT solution precursor


JSI

Excess of PbO: 10 mole %

Dissolution

Reflux (2 h)

Distillation

Sol (CM=0,5)

Zr(n-OBu)4

Ti(n-OBu)4

Pb(OAc)2 / PbO +

CH3-O-CH2CH2-OH Spin-coating

Drying, 200 oC, 2 min

Heating, 400 oC(hot-plate)

Substrate100 nm Pt/ 10 nm TiO2/SiOx/Si

1×(400 oC, 30 min)1×(400 oC, 60 min)

Single-step

4×(400 oC, 5 min)

Multi-step

4x4x


JSI

20 25 30 35 40 45 50

4x(200/2 + 400/5)

*

4x200/2 + 400/30

Pt

P<111>

Si

Int.

(A. u

.)

2 (Deg.)

Properties microstructure

-20 -10 0 10 20

-60

-40

-20

0

20

40

604x200/2 + 400/30

4x(200/2 + 400/5)

P (C/cm2)

E (V)

100 nm

100 nm

Columnar microstructure

Equiaxed grains

M. Mandeljc, M. Kosec, B. Malič, Z. Samardžija, Integrated Ferroelectrics, 30 (2000), 149.M. Mandeljc, M. Kosec, B. Malič, Z. Samardžija, Integrated Ferroelectries, 41 (2001), 163.

Orientation:constant

Design of microstructure by the constant orientation gives a unique possibilities to study microstructure-properties relationship


JSI

400 450 500 550 600 650 70010

15

20

25

30

35

400 450 500 550 600 650 70025

50

75

100

125

150

PZ

T 4

0/6

0, ?

Le

fevre

19

96

PZ

T 3

5/6

5, (1

11

)

K

im 1

99

5

PZ

T 4

0/6

0,

?

M

aki 2

00

2

Pr/(C

/cm2 )

Temperatura, T/oC

Ec/(

kV

/cm

)

Tem.(oC)


JSI

20 25 30 35 40 45 50

PbAc

PbO

(200)

(100)

Pt(111)(111)

Si

Inte

nsity

(A

rb.

units

)

2 (Deg.)

XRD spectra of PZT 30/70 films: effect of lead-source, 4 x (200oC, 2 min.+ 400oC, 5 min.)

Design of orientation by lead source

?


JSI

1-15 min

400oC

Crystallization mechanism


JSI

How can be formed?From Pb in Pt!Pb?From PbO in PZTHow?Reduction?How?Oxidation of organic C+O2= CO22H2+ O2 =2 H2O

Important: amorphous phase must contain enough organic. It is provide by the choice of precursors.

Crystallization mechanism


JSI

to p surfa c eo f the p la ne

So urc ea nd /o r

Re c e ive r

12

Reflect Array antenna

Unit cell of radiating element

Waveguidewith metal iris

Phase shifting components

RETINA: Reliable, tuneable and inexpensive antennas by collective fabrication processes, EU, 6th FP, Thematic priority: Aeronautics and SpaceEADS (D) TAS (F) IMEC (B) EPFL (CH) COV (F) ESIEE (F) JSI (SI) HYB (SI)

-200 -150 -100 -50 0 50 100 150 200

0.18

0.20

0.22

0.24

0.26

0.28

0.30

700oC

C (

pF)

U (V)

900oC


JSI

Temperature dependence of permittivity for BST ceramics

DIE

LE

CT

RIC

CO

NS

TA

NT

BST 30/70

Compositions with a higher Ba-content

At RT:

-Higher permittivity for solid solutions with a higher Ba/Sr ratio but also a higher T-dependence of

-Expected: higher tunability

Tagantsev et al., J. Electroceramics, 2003


JSIBa-acetate + Sr-acetate

0.30 Ba (CH3COO)2 +0.70 Sr(CH3COO)2

Dissolved in acetic acid (100 %), R.T.

CH3COOH

+

Ti n-propoxide

Ti(OC3H7)4

Dissolved in 2-methoxyethanol, R.T., inert atmospere

CH3-O-CH2CH2OH

Mixing at 60oC, inert atmospere

BST-precursor solution (0.25M, 0.4 M)

Ba0.3Sr0.7TiO3 (BST)

Alumina substrate (25.4 x 25.4 mm2) polished, 99.6 %, ε ≈ 9.8)

SpinningPyrolysisCrystallization


JSIMaterials characterization:

Phase composition: XRD (CuKa)

Microstructure: AFM, FE-SEM

Grain size: lineal intercept (~ 100 grains)

Dielectric characterization:

Air-gapped capacitors (0.75 x 1.5 mm2)

Cr/Au electrodes by lift-off photolithography

C (V): 0V+200V0V−200V0V at 1 MHz (JSI)and 8 GHz (V. Cherman, EPFL)

Gap (2-10 m)

BST film

Au/Cr electrode

Alumina substrate Substrate: 25.4 mm x 25.4 mm

Vendik model


JSI

700 °C, 15 min.

100 nm

700 °C, 60 min.

700 °C, 60 min.

100 nm

900 °C, 15 min.

100 nm

900 °C, 60 min.

900 °C, 60 min.

100 nm

FE-SEM images of BST films on alumina annealed at 700 and 900 °C.

Microstructure: effect of annealing conditions

Grain size:40–45nm

Grain size:70 nm

Grain size:80 nm

T increases


JSI

C-V response of BST film on alumina annealed at 700 °C and 900 oC for 60 min. 1MHz, RT, gap width: 8.5 ± 1 m.

Left: surface microstructures of BST films.

-200 -150 -100 -50 0 50 100 150 200

0.18

0.20

0.22

0.24

0.26

0.28

0.30

700oC

C (

pF

)

U (V)

900oC

700oC

900oC

100 nm

100 nm

= 722 ± 50 n = 1.93

= 345 ± 35n = 1.49


JSIThanksDr. Barbara Malič Dr. Janez HolcDr.Marko HrovatDr.Danjela Kuščer-HrovatinDr.Andreja BenčanDr. Tadej RojacDipl. ing.Silvo DrnovšekDipl. ing.Jena Cilenšek Ing. Srečko Maček

Darko Belavič, dipl. ingDr. Marina Santo- ZarnikDr. Mišo VukadinovićMitja Jerlah

Dr. Goran DražičDr.Stojan StavberDr. Vid BobnarProf. Adrijan Levstik

Prof. Nava Setter, EPFL,LausanneProf. Rainer Waser, RWTH AachenMrs. Wanda Wolny, Ferroperm Piezoceramics, Copenhagen

ARRS, EU:LEAF, MINUET, MIND, RETINA

Thank to you!

Documents

JSI Bio-Nano-Space-12-03 - 2008 Jožef Stefan Institute Jamova 39 1000 Ljubljana Slovenija [email protected] Ferroelectrics: Towards Smaller Dimensions