Preparation of Nb doped PZT film by RF sputtering

Undoped lead zirconate titanate (PZT) and Nb doped lead zirconate titanate (PNZT) films formed on an Ir/Ti/SiO2/Si substrate using an RF magnetron sputtering method were studied in detail. Films of about 3–4 μm thickness were deposited at a substrate temperature of 525 ∘C. X-ray diffraction measurement (XRD) shows that the obtained PZT and PNZT films are both strongly uniaxially oriented in the (100) direction of the perovskite structure, and TEM observation shows that the films have columnar structures. The addition of Nb results in changes of film electrical characteristics, particularly dielectric constant and hysteresis characteristics. Sputtered PNZT films (Nb 13 at.%) formed on silicon diaphragm structures generate 2 times more deflections than undoped PZT film formed on the same structure, thus demonstrating a superior piezoelectric performance. A sputtering method to directly form a PNZT film with high piezoelectric constant on a substrate at low temperature via electrodes finds a wide potential use in MEMS applications.