Influence of bias voltage on the structure of lead zirconate titanate piezoelectric films prepared by gas flow sputtering
The work focuses on the influence of ion bombardment on the microstructure of gas flow sputtered lead zirconate titanate (PZT) films. PZT is a well-known piezoelectric material used in many piezoelectric sensor and actuator applications. However, films in the 10 µm thickness region are still in demand for fast and powerful electromechanical drives (e.g. inkjet head). We used the reactive gas flow sputtering technique (GFS) for the high-rate deposition of PZT thin films on platinum- and on Pt/TiO2-coated silicon wafers. The stoichiometry was adjusted to be near the morphotropic phase boundary Pb(Zr0.52Ti0.48)O3 using segmented pure metallic targets. A substrate temperature of 680 °C during growth was applied and the films were prepared with a deposition rate of up to 120 nm · min-1. The perovskite crystalline phase was verified by X-ray diffraction and studies on grain sizes have been performed. The layer morphology was investigated by SEM and films were proved to be mostly crack- and defect-free.