Preparation of Pb(Zr,Ti)O3 thin films on electrodes including IrO2

Abstract

The development of ferroelectric memory devices requires an improvement of the fatigue properties of ferroelectric thin films. Pb(Zr,Ti)O₃(PZT) thin films obtained by the sol‐gel method on Pt/Ti electrodes have reduced residual polarization by continuous polarization reverses about of 10⁸ cycles. The electric characteristics such as fatigue properties have mostly depended on electrode materials. We propose Ir, IrO₂, and these layer films as electrode materials and evaluate electric characteristics of PZT thin film capacitors. PZT thin films using Ir/IrO₂ and Pt/IrO₂ electrodes show no fatigue up to 10¹² cycles of ±5 V switching pulses. Moreover, good properties of PZT capacitors, not only on SiO₂ but also on polycrystalline silicon, were obtained by using IrO₂.