Fabrication and characteristics of microelectromechanical system device based on PZT films and surface micromachining

Abstract

Microelectromechanical system processes based on surface micromachining technique were studied to fabricate the electrical devices on silicon wafer such as cantilever beam accelerometers and uncooled IR-detectors. In recent, a short problem of the PZT film deposited by metalorganic decomposition after fabricating processes made the device's failure. In this article, solutions of this short problem and characteristics of the PZT films before and after micromachining processes are studied to investigate the influence of device etching processes on the final device characteristics. The remanent polarization values (at 15 V) of the PZT film on the Pt/Ti without processes and with processes are around 54 mu C/cm(2) and 28 mu C/cm(2), respectively. A possible simple model for the decrease of polarization after etching processes will be suggested. Piezoelectric coefficient (at 4 V) measured by single beam laser interferometer, d(33) Of the PZT film on Pt/Ti and RuO2/Ru are around 80 pm/V and 41 pm/V, respectively. The PZT films on the RuO2/Ru and Pt/RuO2 had almost the same remanent polarization and piezoelectric coefficient before and after etching process while the film on Pt/Ti did not. These results suggest that the RuO2/Ru and Pt/RuO2 hybrid conducting materials as a bottom electrode are good for MEMS based on surface micromachining technique.