Fatigue-free La-modified Pb(Zr,Ti)O-3 capacitors using a seed layer

Abstract

The development of lead zirconate titanate (PZT)-based capacitors using common Pt electrodes has been a long-time goal of ferroelectric random access memories (FRAM). In this work, a series of Pb1-xLax(Zr0.55Ti0.45)O-3 capacitors (for 0.01 less than or equal to x less than or equal to 0.05) having fatigue-free characteristics have been grown on Pt/Ti/SiO2/Si substrates. Typically 2-3 mol% La-modified PZT capacitors fabricated at 580 degreesC by applying a PZT seed layer exhibited fatigue-free behavior up to 6.5 x 10(10) switching cycles, a low coercive field of 50-55 kV/cm, and a stable charge retention profile with time, all of which assure their suitability for the future nonvolatile FRAM.