Nuclear Reaction Probe of Oxygen Vacancy Migration in Electrically Fatigued PZT Thin Film Capacitors

ABSTRACTThe migration of oxygen vacancies and their entrapment near film-electrode interfaces has been proposed as a cause of fatigue (i.e., polarization weakening) in ferroelectric thin film capacitors. To test this idea, lead zirconate titanate (PZT) thin films were epitaxially deposited by laser ablation on LaAlO3 substrates with yttrium barium cuprate (YBCO) base electrodes. Thin film capacitors were formed by deposition of noble metal (Pt) cap electrodes; half of them were then electrically fatigued by repeated polarization reversals (108 cycles). The distributions of oxygen in the two halves were then compared by means of accelerator-based nuclear backscattering (using the narrow elastic resonance at 3.045 MeV in the scattering of 4He from 16O) throughout the bulk of the PZT films and especially right under the Pt electrodes. We were unable to detect any difference in the oxygen profiles to within the accuracy of measurement, which was about 1 % of the oxygen concentration. Compositional changes, at least involving oxygen, do not seem to be responsible for the striking electrical alterations seen in fatigued PZT.

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Correlations Among Degradations in Lead Zirconate Titanate thin Film Capacitors

MRS Proceedings ◽

10.1557/proc-310-165 ◽

1993 ◽

Vol 310 ◽

Cited By ~ 69

Author(s):

In K. Yoo ◽

Seshu B. Desu ◽

Jimmy Xing

Keyword(s):

Thin Film ◽

Leakage Current ◽

Lead Zirconate Titanate ◽

Oxygen Vacancies ◽

Lead Zirconate ◽

Electrical Degradation ◽

Zirconate Titanate ◽

Thin Film Capacitors ◽

Pzt Thin Film ◽

Degradation Properties

AbstractMany attempts have been made to reduce degradation properties of Lead Zirconate Titanate (PZT) thin film capacitors. Although each degradation property has been studied extensively for the sake of material improvement, it is desired that they be understood in a unified manner in order to reduce degradation properties simultaneously. This can be achieved if a common source(s) of degradations is identified and controlled. In the past it was noticed that oxygen vacancies play a key role in fatigue, leakage current, and electrical degradation/breakdown of PZT films. It is now known that space charges (oxygen vacancies, mainly) affect ageing, too. Therefore, a quantitative ageing mechanism is proposed based on oxygen vacancy migration under internal field generated by either remanent polarization or spontaneous polarization. Fatigue, leakage current, electrical degradation, and polarization reversal mechanisms are correlated with the ageing mechanism in order to establish guidelines for simultaneous degradation control of PZT thin film capacitors. In addition, the current pitfalls in the ferroelectric test circuit is discussed, which may cause false retention, imprint, and ageing.

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Lead zirconate titanate ferroelectric thin film capacitors: Effects of surface treatments on ferroelectric properties

Applied Physics Letters ◽

10.1063/1.2769394 ◽

2007 ◽

Vol 91 (7) ◽

pp. 072910 ◽

Cited By ~ 14

Author(s):

Ye Chen ◽

Paul C. McIntyre

Keyword(s):

Thin Film ◽

Lead Zirconate Titanate ◽

Ferroelectric Properties ◽

Ferroelectric Thin Film ◽

Lead Zirconate ◽

Surface Treatments ◽

Zirconate Titanate ◽

Thin Film Capacitors

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Breakdown in lead zirconate titanate (PZT) thin film capacitors

Proceedings of 1994 IEEE International Symposium on Applications of Ferroelectrics ◽

10.1109/isaf.1994.522422 ◽

2002 ◽

Author(s):

In Kyeong Yoo ◽

Seshu Babu Desu

Keyword(s):

Thin Film ◽

Lead Zirconate Titanate ◽

Lead Zirconate ◽

Zirconate Titanate ◽

Thin Film Capacitors ◽

Pzt Thin Film

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Domain behavior in lead zirconate titanate (PZT) thin film capacitors

Integrated Ferroelectrics ◽

10.1080/10584589508019376 ◽

1995 ◽

Vol 6 (1-4) ◽

pp. 329-336

Author(s):

In Kyeog Yoo ◽

Seshu B. Desu

Keyword(s):

Thin Film ◽

Lead Zirconate Titanate ◽

Lead Zirconate ◽

Zirconate Titanate ◽

Thin Film Capacitors ◽

Pzt Thin Film

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Photo-Induced Polarization Recovery in PZT Thin Film Capacitors

MRS Proceedings ◽

10.1557/proc-459-201 ◽

1996 ◽

Vol 459 ◽

Author(s):

S. A. Mansour ◽

A. V. Rao ◽

A. L. Bement ◽

G. Liedl

Keyword(s):

Thin Film ◽

Lead Zirconate Titanate ◽

White Light ◽

Indium Tin Oxide ◽

Monochromatic Light ◽

Rf Sputtering ◽

Ferroelectric Thin Film ◽

Lead Zirconate ◽

Thin Film Capacitors ◽

Induced Changes

ABSTRACTLead Zirconate Titanate (PZT) ferroelectric thin film capacitors were fabricated with metallic platinum and conducting Indium Tin Oxide (ITO) contacts. PZT thin films were fabricated using metallorganic decomposition (MOD) while a combination of MOD and RF-sputtering was used in fabricating the ITO-PZT-ITO capacitors. Photo-induced changes, manifested by an increase in switchable polarization, were studied before and after 108 switching cycles fatigue using white and monochromatic light. An increase in photo-induced changes was observed at 3.65eV light energies using monochromatic light using both capacitors. The increase was attributed to the excitation of electrons from PZT valence band into the conduction band causing an increase in film conductivity. However, polarization increase in Pt-PZT-Pt capacitor was more pronounced than ITO-PZT-ITO when white light was used. Some of the response in fatigued Pt-PZT-Pt capacitors was attributed to the excitation of electrons from the platinum Fermi level to oxygen vacancy sites trapped at the Pt-PZT interface by absorption of infrared radiation of white light. The latter observation implied a relationship between PZT fatigue and photo-induced effects.

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