Ferroelectric fatigue of Pb(Zr,Ti)O3 thin films measured in atmospheres of varying oxygen concentration

Abstract

Ferroelectric fatigue in Pb(Zr,Ti)O3 films was found to be remarkably sensitive to the oxygen partial pressure of the atmosphere above the film during measurement. Films with Zr/Ti ratios of 55/45 and 75/25 were subjected to ferroelectric fatigue testing at room temperature in atmospheres of various oxygen partial pressure, or pO2. The number of switching cycles at which the onset of fatigue occurred was found to be sharply peaked with respect to the oxygen partial pressure surrounding the sample. Such a striking dependence on the oxygen concentration strongly supports current theories for fatigue that involve oxygen vacancy migration.

High oxygen-pressure annealing effects on the ferroelectric and structural properties of PbZr0.3Ti0.7O3 thin films

“…17 In addition, measurements of the ferroelectric fatigue in Pb͑Zr, Ti͒O 3 thin films revealed a sensible dependence on the oxygen partial pressure of the atmosphere applied during the measurement. 18 The results of a recent work also indicated that the crystallization degree of PZT thin films is enhanced when a high-pressure crystallization process is performed in air and at temperatures as low as ϳ350°C. Such a procedure resulted in a decrease of the temperature in which the crystallization of these PbZr 0.4 Ti 0.6 O 3 thin films occurs.…”

“…15,16 The electric properties of these PZT films are also influenced by the synthesis and the conditions used during deposition or annealing procedure. [17][18][19] Some studies revealed that annealing under reducing conditions ͑H 2 +Ar͒ promote an increase of the leakage current and a severe decrease of the ferroelectric polarization in PbZr 0.48 Ti 0.52 O 3 compounds. 17 In addition, measurements of the ferroelectric fatigue in Pb͑Zr, Ti͒O 3 thin films revealed a sensible dependence on the oxygen partial pressure of the atmosphere applied during the measurement.…”

Negligible oxygen liberation during bipolar electric cycling of ferroelectric lead zirconate titanate ceramics

“…This seems reasonable since oxygen vacancies are known to be the most mobile defect in lead zirconate titanate ͑PZT͒ at room temperature. [1][2][3] The most striking experiment was conducted by Brazier et al 4 who found that the fatigue rate depends on the oxygen partial pressure surrounding a thin film sample during cycling. Pan et al 5 observed gas bubbles in the surrounding fluid, Fluorinert ® , during cycling and detected oxygen in the escaping gas by means of gas chromatography.…”

Polarization Fatigue of NiCr/PZT/BaPbO3Capacitors on Platinized Silicon Wafers

“…In order to explain the mechanism of fatigue, a number of models have been proposed [1][2][3][4][5][6][7][8][9][10], but the origin of fatigue is still under debate. The accumulation of oxygen vacancies at electrodes via diffusion at the PZT-Pt interface [1][2][3][4][5]9], the formation of interface layers near the electrodes which efficiently reduce the electric field across the ferroelectric layer or inhibit the nucleation of oppositely polarized domains [5], and the locking domains by oxygen vacancy-induced electronic charges which are trapped at domain boundaries [6,7] are considered to be the reason for the fatigue.…”