Fatigue behaviour of Pb(Zr,Ti)O3/PbZrO3 multilayer ferroelectric thin films

Abstract

Fatigue behaviour of Pb(Zr0.45Ti0.55)O-3 (PZT) thin films on Pt-(111)/Ti/SiO2/Si-(100) substrates with PbZrO3 (PZ) buffer layers were investigated. Two different buffer layer configurations were studied: bottom- and top-only buffer layers. The PZ buffer layers were obtained by RF magnetron sputtering of a loose powder target containing a mixture of PbZrO3 and ZrO2 powders. The PZT thin films were prepared by sol-gel spin coating method. All of the films had well-crystallized, uniform and dense microstructure with full (111) orientation. The bottom buffer layers influenced the nucleation and grain growth of the upper PZT layers creating a bimodal grain size distribution. Secondary ion mass spectrometry (SIMS) elemental depth profiles indicated that a PZ buffer layer led to well-defined and sharp composition profiles. The P-E hysteresis measurements indicated comparable remnant polarization values (2P(r) = 40-50 mu C/Cm-2) and coercive field levels (2E(c) = 150-180 kV/cm) with un-buffered film. The fatigue endurance of PZT thin films with PZ buffer layers was superior than the un-buffered, counterpart. A fatigue-free. behaviour was observed up to 109 switching cycles.