Fatigue and retention behaviors of Pt-PZT-metal capacitors with various top metallizations

The PZT-substrate or PZT-electrode interface can affect the FE properties and specifically the fatigue behaviour. Typical Pt-PZT-Pt capacitors exhibited fatigue resistance up to 10⁸-10⁹ cycles, while RuO₂, La_0.5Sr_0.5CoO₃ and YBa₂Cu ₃O₇ electrodes have been reported in literature to yield fatigue-free devices up to 10¹¹-10¹² cycles. In an early study which compared the fatigue behaviour of bulk PLZT ceramics with various metal electrodes, it was found that In offered the best fatigue performance (up to 10⁹ cycles). A series of sol-gel derived PZT 53/47 films were fired to 700C to achieve single-phase FE perovskite films. Bottom electrode (or the substrate) consisted of sputtered Pt on oxidized Si wafers. Monolithic capacitors were obtained by depositing top electrodes of Ag, Au, Au-Pd, Pd and Pt. All the capacitors exhibited fatigue, manifested by lower values of P _r, E_c and ε_r but higher leakage currents after cycling