Reliability of piezoelectric films for MEMS
Susan Trolier‐McKinstry, Wanlin Zhu, Betul Akkopru‐Akgun, Fan He, Song Won Ko, Charalampos Fragkiadakis, Peter Mardilovich
Abstract
Abstract Thin films based on PbZr 1− x Ti x O 3 and K 1− x Na x NbO 3 are increasingly being commercialized in piezoelectric MEMS due to the comparatively low drive voltages required relative to bulk actuators, as well as the facile approach to making sensor or actuator arrays. As these materials are incorporated into devices, it is critically important that they operate reliably over the lifetime of the system. This paper discusses some of the factors controlling the electrical and electromechanical reliability of lead zirconate titanate (PZT)-based piezoMEMS films. In particular, it will be shown the gradients in the Zr/Ti ratio through the depth of the films are useful in increasing the lifetime of the films under DC electrical stresses.