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

TLDR

Ferroelectric memory devices require improved fatigue properties, which largely depend on electrode materials. The study proposes using Ir and IrO2 layers as electrode materials for PZT thin‑film capacitors. The authors evaluate the electric characteristics of these capacitors. PZT thin films on Pt/Ti electrodes show reduced residual polarization after ~10^8 cycles, while films with Ir/IrO2 and Pt/IrO2 electrodes exhibit no fatigue up to 10^12 cycles and perform well on SiO2 and polycrystalline silicon.

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.