Reliability of piezoelectric films for MEMS

Abstract

Thin films based on PbZr1-xTixO3 and K1-xNaxNbO3 are increasingly being commercialized in piezoelectric microelectromechanical systems (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 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.