Adjustable response of PZT thin film based piezoelectric micro-actuator through DC bias pre-polarization

Abstract

PZT piezoelectric thin film based technology is promising in the field of micro-actuators. This paper discusses the effects of pre-polarization on the key properties of PZT thin film, and explores the improvement rules of pre-polarization from the material to device level experiments. At the material level, the pre-polarization treatment increases the piezoelectric strain coefficient by 25%, and improves dielectric properties. Meanwhile, in ferroelectric properties the pre-polarization treatment increases the residual polarization by 50% and coercive field by 25%, respectively. At the device level, pre-polarization treatment greatly increases the output characteristics of the devices, such as maximum output displacement increasing by at least 45% and withstand voltage enhancing by 2 V, which is consistent with the material level enhancement. In addition, the optimal pre-polarization process conditions and the long-term stability of the performance improvement are investigated. The pre-polarization treatment has proved to be meaningful for the improvement of the output capability of the piezoelectric thin film actuators.