Fabrication of Planar and Three-Dimensional PZT Capacitors with Ir-Based Electrodes Solely by Low-Temperature MOCVD Using a Novel Liquid Ir Precursor

Abstract

We report on preparation of Ir and IrO2 electrodes and its applications to planar and three-dimensional (3D) PZT capacitors solely by MOCVD using a novel liquid Ir precursor, Ir(EtCp) (CHD). Continuous 15–50 nm-thick Ir films with a pure metallic phase were successfully grown at 250-350°C on SiO2/Si without an incubation time. Ir electrodes showed 40–60% step coverage on stepped substrates with aspect ratios of 0.5–2.0. Fatigue free planar and 3D-Ir/PZT/Ir capacitors with 2Pr of 27–36 μ C/cm2 were successfully fabricated solely by MOCVD. IrO2 electrodes were grown at 400°C by 2-step MOCVD using surface oxidized Ir seeds. Planar PZT capacitors with IrO2 bottom and Ir top electrodes showed D-E hysteresis loops with 2Pr of 27 μ C/cm2 and endurance property with no degradation up to 1010 switching cycles by bipolar pulses of ± 5 V and 500 kHz.