Synthesis of 10‐μm‐Thick Lead Zirconate Titanate Films on 2‐in. Si Substrates for Piezoelectric Film Devices

To achieve micro‐machined piezoelectric film devices, crack‐free and dense 10‐μm‐thick lead zirconate titanate (PZT) films were successfully deposited onto 2‐in. Pt/Ti/SiO ₂ /Si substrates using an automatic coating system, and disk‐shaped structures with a diameter from 20 to 100 μm were fabricated by an RIE process. The prepared PZT thick film disks showed well‐saturated P–E hysteresis curves and butterfly‐shaped longitudinal displacement curves. The AFM‐measured piezoelectric constant of the 30‐μm‐diameter PZT thick film disk after poling at 100 V for 10 min was AFM d ₃₃ =290 pm/V. The resonant and anti‐resonant frequencies of the thickness oscillation mode were observed at 180 MHz. The calculated thickness mode effective coupling factor was ( k _eff ) ² =0.1 for the poled 30‐μm‐diameter PZT thick film disks. These results suggest that the prepared PZT thick film disks are applicable for piezoelectric micro devices such as micro‐machined ultrasonic transducers.