Investigation of metal-ferroelectric interfaces at micro and nanometric level (Investigarea interfetelor metal- feroelectric la nivel micro si nanometric)

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Investigation of metal-ferroelectric interfaces
at micro and nanometric level(Investigarea
interfetelor metal- feroelectric la nivel micro
si nanometric)

• IFA-CEA cooperation program
• Presenting Dr. Lucian Pintilie
• Project responsible from the Romanian part

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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 metal-ferroelectric-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
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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 CEA team
Project leader (Name) Dr. Pintilie Lucian Dr. LE RHUN Gwenaël
Laboratory Institution Address Tel  Fax  e-mail Head of laboratory Laboratory Multifunctional Materials and Structures National Institute of Materials Physics Atomistilor 105bis, Magurele 077125, Romania 40-(0)21-3690185 40-(0)21-3690177 pintilie_at_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_at_cea.fr AID Marc Grown of STO on Si substrate, and of PZT on SRO/STO/Si preliminary electrical characterization
RO team CEA 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 Dr. Gwenaël Le Rhun (young researcher) Dr. Emmanuel Defaÿ Shi YIN (young researcher)
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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
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Local piezoelectric hysteresis
The stability of the polarization on the bare
surface
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Ipoteza 1 tot O Ipoteza 1 tot O Ipoteza 2 fara O (c4) Ipoteza 2 fara O (c4) Ipoteza 3 fara O (c3 c4) Ipoteza 3 fara O (c3 c4) Ipoteza 3 fara O (c3 c4)
Componente comp. at. total at. comp. at. total at. comp. at. total at. total at.
O 1s (1) 1.01 66.65 1.18 60.97 1.42 1.42 53.11
O 1s (2) 36.73 43.02 51.68 51.68
O 1s (3) 14.32 16.77 fara 20.15 fara 20.15
O 1s (4) 14.59 fara 17.09 fara 20.53 fara 20.53
Ti 2p (1) 1.88 10.87 2.21 12.73 2.66 2.66 15.29
Ti 2p (2) 4.04 4.73 5.69 5.69
Ti 2p (3) 4.9 5.78 6.95 6.95
Zr 3d (1) 0.66 3.56 0.77 4.17 0.92 0.92 5.02
Zr 3d (2) 2.63 3.08 3.71 3.71
Zr 3d (3) 0.274 0.32 0.38 0.38
Pb 4f (1) 16.22 18.89 18.99 22.12 22.82 22.82 26.58
Pb 4f (2) 2.18 2.55 3.07 3.07
Pb 4f (3) 0.48 0.56 0.68 0.68
Suma 99.914 117.05 140.66 140.66

Pb 1.31 Ti 0.75 Zr 0.25 O 4.62 Pb 1.31 Ti 0.75 Zr 0.25 O 4.62 Pb 1.31 Ti 0.75 Zr 0.25 O 3.61 Pb 1.31 Ti 0.75 Zr 0.25 O 3.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61
Pb 1.31 Ti 0.75 Zr 0.25 O 4.62 Pb 1.31 Ti 0.75 Zr 0.25 O 4.62 Pb 1.31 Ti 0.75 Zr 0.25 O 3.61 Pb 1.31 Ti 0.75 Zr 0.25 O 3.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61
Pb 1.31 Ti 0.75 Zr 0.25 O 4.62 Pb 1.31 Ti 0.75 Zr 0.25 O 4.62 Pb 1.31 Ti 0.75 Zr 0.25 O 3.61 Pb 1.31 Ti 0.75 Zr 0.25 O 3.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61
Pb 1.31 Ti 0.75 Zr 0.25 O 4.62 Pb 1.31 Ti 0.75 Zr 0.25 O 4.62 Pb 1.31 Ti 0.75 Zr 0.25 O 3.61 Pb 1.31 Ti 0.75 Zr 0.25 O 3.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61 Pb 1.31 Ti 0.75 Zr 0.25 O 2.61
Nivel ASF Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi Pozitie niveluri energetice (eV) in diferiti compusi
Nivel ASF Pb Ti Ti Zr PbO PbO2 TiO2 ZrO2 PbTiO3 PbZrO3 Au
O 1s 0.66 - - - - 529.3 529.0 530.0 529.9 529.9 ? -
Ti 2p 1.8 - 454 454 - - - 459.0 - 458.6 - -
Zr 3d 2.1 178.9 - - - 183.3 - ? -
Pb 4f 6.7 136.9 136.9 - - 137.6 137.4 - - 139.0 138.5 -
Au 4f 4.95 - - - - - - - - - - 83.8
Results of XPS analysis -surface is depleted in
oxygen -some PbCO3 and PbO forms at the surface
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Behavior of short-circuit current for different
electrodes
Changes observed after treatment in oxygen plasma
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PFM studies on PZT52/48 films deposited in
France, above the SRO film deposited in Romania
by PLD
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Results French team
Figure 1 RHEED images at the end of STO
deposition
Figure 2 2?/? 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
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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 metal-ferroelectric-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.

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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-d single crystal
films, sent to PHYSICA STATUS SOLIDI-RAPID
RESEARCH LETTERS