Process dependence of the piezoelectric response of membrane actuators based on PZT thin films

A process for the fabrication of piezoelectric membranes with Pb(Zr0.45Ti0.55)O3 (PZT) thin films for micrometer-range actuation and sensing applications has been developed. The films grown by sol-gel on the Pt/Ti/SiO2/SOI (silicon-on-insulator) substrates have similar randomly oriented perovskite phases, but the nearly epitaxial film made by the pulsed laser deposition exhibits a more compact and flat morphology. It is observed that a denser microstructure produced by pulsed laser deposition leads to a significantly higher remanent polarization and piezoelectric coefficient in the capacitor structure, as well as in a much higher piezoelectric membrane displacement, but only a slightly enhancement of the quality factor of the membrane actuator is obtained. The membrane actuator with the epitaxial PZT thin film grown on a SrRuO3/Yttria-Stabilized Zirconia/SOI substrate using pulsed laser deposition shows significantly enhanced piezoelectric membrane displacement and quality factor. The results and discussion in our paper provide a better understanding of the relationship between the microstructure and the thin film properties, which may lead to significant improvements in device performance