Investigation of metal-ferroelectric
interfaces at micro and nanometric level
(Investigarea interfeţelor metal- feroelectric
la nivel micro şi nanometric)
IFA-CEA cooperation program
Presenting: Dr. Lucian Pintilie
Project responsible from the Romanian part
IFA-CEA symposium 20 of October 2011,
Magurele
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Scope of the project
The main objective of the project will be to study the construction of the
metal-ferroelectric interface and the dynamic of charge compensation in
relation to polarization switching. The results will be compared to the results
of the macroscopic electric measurements performed on standard metalferroelectric-metal (MFM) capacitors. Also, the metal-ferroelectric interface
will be compared with the results reported for the free surface.
Important milestones
End of the 1st year-deposition and characterization of epitaxial PZT films;
conclusions regarding the charge compensation on the free surface
End of the 2nd year-formation of metal-PZT interface and characterization through
surface/interace investigation techniques; charge compensation at the interface
End of the 3rd year-macroscopic-microscopic correlation
IFA-CEA symposium 20 of October 2011,
Magurele
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Teams and collaboration
There is a common interest in the proposed topic. The responsible of the Romanian part has
collaborated with Dr. Gweneal Le Rhun, member of the CEA team, during their workstages at MPI
Halle, Germany. Dr. Pintilie was visiting scientists while dr. Le Rhun was a Humboldt fellow. A few
common papers resulted from this collaboration (see the list below). The present project will help
to develop the collaboration between the two teams to a new level.
RO team
Project leader
(Name)
Laboratory
Institution
Address
Tel :
Fax :
e-mail:
Head of
laboratory
CEA team
Dr. Pintilie Lucian
Dr. LE RHUN Gwenaël
Laboratory Multifunctional Materials and
Structures
National Institute of Materials Physics
Atomistilor 105bis, Magurele 077125, Romania
+40-(0)21-3690185
+40-(0)21-3690177
pintilie@infim.ro
Dr. Ionut Enculescu
Grown of SRO layer on STO/Si substrates;
grown of PZT/SRO on single crystal STO
substrates; surface/interface investigation;
electrical measurements with temperature;
comparison with samples from France
RF Components Laboratory
CEA
17 rue des Martyrs, 38054 Grenoble Cedex 9,
FRANCE
+33-(0)4-38784042
+40-(0)4-38782434
gwenael.le-rhun@cea.fr
AID Marc
Grown of STO on Si substrate, and of PZT on
SRO/STO/Si; preliminary electrical
characterization
RO team
Dr. Lucian Pintilie
Dr. Stancu Viorica (young researcher)
Dr. Ioana Pintilie
Dr. Cristian Mihail Teodorescu
Drd. Cristina Dragoi (young researcher)
Drd. Marius Husanu (young researcher)
Drd. Lucian Trupina
CEA team
Dr. Gwenaël Le Rhun (young researcher)
Dr. Emmanuel Defaÿ
Shi YIN (young researcher)
IFA-CEA symposium 20 of October 2011,
Magurele
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Results: Romanian team
AFM pictures of STO substrate (left), SRO film (middle) and PZT film (right)
HR-TEM picture of the PZT-SRO-STO interfaces
IFA-CEA symposium 20 of October 2011,
Magurele
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40
d33 (pm/V)
20
0
-20
-40
-3
-2
-1
0
1
2
3
Vdc
Local piezoelectric hysteresis
The stability of the polarization on the bare surface
IFA-CEA symposium 20 of October 2011,
Magurele
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Compone
nte
O 1s (1)
O 1s (2)
O 1s (3)
O 1s (4)
Ti 2p (1)
Ti 2p (2)
Ti 2p (3)
Zr 3d (1)
Zr 3d (2)
Zr 3d (3)
Pb 4f (1)
Pb 4f (2)
Pb 4f (3)
Suma
Ipoteza 2: fara O
Ipoteza 3:
Ipoteza 1: tot O
(c4)
fara O (c3 + c4)
comp.
total
comp.
total
comp.
total at.
at. %
at. %
at. %
at. % at. %
%
1.01
66.65
1.18 60.97
1.42 53.11
36.73
43.02
51.68
fara
14.32
16.77
[20.15]
fara
fara
14.59
[17.09]
[20.53]
1.88
10.87
2.21 12.73
2.66 15.29
4.04
4.73
5.69
4.9
5.78
6.95
0.66
3.56
0.77
4.17
0.92
5.02
2.63
3.08
3.71
0.274
0.32
0.38
16.22
18.89
18.99 22.12
22.82 26.58
2.18
2.55
3.07
0.48
0.56
0.68
99.914
117.05
140.66
Pb 1.31
Ti 0.75
Zr 0.25
O 4.62
Nivel
O 1s
Ti 2p
Zr 3d
Pb 4f
Au 4f
ASF
0.66
1.8
2.1
6.7
4.95
Pb
-
Ti
454
136.9
-
-
Pozitie niveluri energetice (eV) in diferiti compusi
Zr
PbO
PbO2
TiO2
ZrO2
PbTiO3
529.3 529.0 530.0 529.9
529.9
459.0 458.6
178.9 183.3
137.6 137.4 139.0
-
PbZrO3
?
?
138.5
-
Au
83.8
IFA-CEA symposium 20 of October 2011,
Magurele
Pb 1.31
Ti 0.75
Zr 0.25
O 3.61
Pb 1.31
Ti 0.75
Zr 0.25
O 2.61
Results of XPS analysis:
-surface is depleted in oxygen
-some PbCO3 and PbO forms at
the surface
6
Behavior of short-circuit current for
different electrodes
Changes observed after treatment in oxygen plasma
IFA-CEA symposium 20 of October 2011,
Magurele
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PFM studies on PZT52/48 films deposited in France, above the SRO film
deposited in Romania by PLD
IFA-CEA symposium 20 of October 2011,
Magurele
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Results: French team
Figure 1: RHEED images at the end of STO deposition
Figure 2: 2θ/ω scan on PZT deposited on STO/Si
Hysteresis and C-V curves for PZT52/48 films deposited by
sol-gel in France, above the SRO layer deposited by PLD
in Romania
IFA-CEA symposium 20 of October 2011,
Magurele
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Benefits of the collaboration
Romanian team:
- Has learned that STO can be epitaxially grown on Si
- Has the opportunity to compare the results obtained on epitaxial PZT films
grown by sol-gel with those of the films grown by PLD
French team:
-Can grow the PZT films on SRO layers, thus can develop metalferroelectric-metal structures
- Has the opportunity to compare the results obtained on epitaxial PZT films
grown by sol-gel with those of the films grown by PLD
Observation:
Due to some organizational problems on the French side, which generated
delays in getting the financial support, it was not possible to exchange visits
in the first year of the project.
IFA-CEA symposium 20 of October 2011,
Magurele
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Perspectives for the next years
Foreseen common activities:
- Finalizing the comparison of surface properties and PFM results on sol-gel
and PLD deposited PZT52/48 films both on SRO/STO/Si and SRO/STO(sc)
substrates
-Testing common metals used in microelectronics (Cu, Au, Al) as electrodes
and compare the results on sol-gel and PLD deposited films
- Studying the electrode-PZT interface by various methods, with emphasis on
PFM and PLD
Publications:
L. Pintilie, C. Dragoi, and I. Pintilie, “Interface controlled photovoltaic effect in epitaxial Pb(Zr,Ti)O3 films
with tetragonal structure”, JOURNAL OF APPLIED PHYSICS 110, 044105 (2011)
L. Pintilie, C. Dragoi, V. Stancu, G. Ibanescu, I. Pintilie, “Effect of microstructure and electrode interface on
the hysteretic behavior of ferroelectric Pb(Zr,Ti)O3 thin films”, sent to JOURNAL OF PHYSICSD: APPLIED
PHYSICS
N.G. Gheorghe, G.A. Lungu, C.M. Teodorescu, I. Pintilie, L. Trupina, C. Dragoi, “Photoelectron spectroscopy
studies of pulsed laser deposited Pb(Zr,Ti)O3-δ single crystal films”, sent to PHYSICA STATUS SOLIDIRAPID RESEARCH LETTERS
IFA-CEA symposium 20 of October 2011,
Magurele
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