Fatigue-free lead zirconate titanate-based capacitors for nonvolatile memories

Abstract

The development of lead zirconate titanate (PZT)-based capacitors has been a long time goal of ferroelectric random access memories (FRAM). However, PZT-based perovskites with common platinum (Pt) electrodes have suffered from a significant reduction of the remanent polarization (P-r) after a certain number of read/write cycles (electrical fatigue). We now report the development of fatigue-free lanthanum-modified PZT capacitors using common Pt electrodes. The capacitors fabricated at 580 degreesC by applying a PZT seed layer exhibited fatigue-free behavior up to 6.5x10(10) switching cycles, a quite stable charge retention profile with time, and comparatively high P-r values, all of which assure their suitability for practical FRAM applications. (C) 2001 American Institute of Physics.