Bio-Nano-Space-12-03 -2008
JSI
Jožef Stefan InstituteJamova 39
1000 LjubljanaSlovenija
Ferroelectrics: Towards Smaller Dimensionsand Complex Structure
Marija Kosec
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
JSI
Powder synth.
shaping
firing
thick film
Thick film procesing
screen printing ink jet printing electrophoretic deposition
Squeegee
Paste
Mask
Substrate
Screen
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
JSI
Microstructure after firing 1h 850oC.
LTCC/PZT barriere/Au/PZT/Au
LTCC/Au/PZT/ Au
Bio-Nano-Space-12-03 -2008
JSI
displacement
200V=3µm
dimensions 12.0 × 4.0 × 0.22 mm - 40µm thick PZT
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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)
Bio-Nano-Space-12-03 -2008
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
?
Bio-Nano-Space-12-03 -2008
JSI
1-15 min
400oC
Crystallization mechanism
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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
Bio-Nano-Space-12-03 -2008
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!