Polarization recovery of fatigued Pb(Zr,Ti)O3 thin films: Switching current studies

Abstract

In the process of fatiguing Ir/Pb(Zr0.35Ti0.65)O3/Pt capacitors we have observed the splitting and separation of both the positive and negative switching currents into two distinct peaks. By measuring the current response to a post-fatigue, triangular, voltage waveform, we have observed a shift of the majority of the switching current to higher voltages and, eventually, beyond the voltage testing range. At high fatigue cycle numbers, this current peak shift is large enough to reveal a smaller switching current peak whose position remains invariant. Subsequent higher amplitude switching pulses access the high coercive voltage switching peaks, returning the remanent polarization values, though not the overall switching profile, to unfatigued levels. Pulse polarization measurements reveal that the switchable polarization that appears lost at lower testing voltages is highly recoverable when higher voltages are applied. Thus, the fatigue cycling appears to primarily increase the polarization switching resistance while inducing very little irrecoverable switching loss. Finally, we measured increased resistance to switching with fatigue cycling even when the majority of the capacitor volume was no longer switching during the fatigue pulses, suggesting that only voltage cycling, and not the concomitant polarization switching, are necessary to induce fatigue.

Polarization recovery in lead zirconate titanate thin films deposited on nanosheets-buffered Si (001)

“…Similar kind of polarization recovery by applying higher electric field has been reported previously for PZT films deposited on Pt electrodes, although no physical description for the occurrence is included. 34 The observed fatigue phenomenon and its recovery can be explained using Dawber-Scott model and kinetic approach of the fatigue. According to Dawber-Scott model the charged defects such as oxygen vacancies accumulate easily near film-electrode interfaces and results in the formation of space-charge layers under the influence of an external field.…”

Ferroelectric characterization of nondensified particle-based structures

“…Instead of measuring the integrated charge directly ͑Sawyer-Tower or virtual ground circuit͒, we record the switching current by monitoring the potential drop across a tunable reference resistor placed in series to the ferroelectric capacitor ͑shunt method, 44 Fig. 4͒ with an oscilloscope.…”

Influence of fatigue processes on the switching currents in lead titanate and lead zirconate-titanate films

“…These materials are exemplified by thin ferro electric films, which exhibit a high field controlled permittivity, a significant frequency dispersion of the properties, and a high dielectric nonlinearity [1][2][3]. The successful implementation and exploitation of ferroelectric memory cells necessitate a detailed inves tigation of the polarization switching processes and peculiarities of formation and kinetics of the domain structure in thin polycrystalline films, including the aging and fatigue processes, which exhibit themselves in deterioration of the properties with time and a decrease in the switchable charge after multiply repeated switching (fatigue) [4][5][6][7][8][9].…”