Fabrication of PZT microdevices using a high-yield sol-gel process

Abstract

Piezoelectric micro devices based on lead zirconate titanate (PZT) thin film have received considerable attention because of their wide potential in nanotechnology, biosensors and microelectromechanical systems. Thin film cracking, device short-circuiting and substrate surface degrading are commonly encountered problems for PZT micro device fabrication using chemical solution deposition (or CSD) process. These problems often lead to an extreme low yield (<10%) of fabrication and hinder the integration of piezoelectric components into micro-electromechanical systems. In this work, a new manufacturing method for PZT micro devices is developed for the first time to avoid all these problems. Unlike other modified PZT sol-gel processes, in our process pyrolysised PZT thin film is patterned by wet etching before (rather than after) the high temperature sintering treatment. This new process can tremendously reduce the cracking of thin film and eradicate the diffusion of PZT to those substrate surfaces without Pt buffer layer. The effectiveness of the process is proved by 1) the 100% fabrication yield of a number of PZT micro cantilevers, bridges and platforms, 2) the complete elimination of contaminated surfaces by PZT diffusion.