FABRICATION AND CHARACTERISTICS OF MICROELECTROMECHANICAL SYSTEM DEVICE BASED ON PZT FILMS AND SURFACE MICROMACHINING

Microelectromechanical system processes based on surface micromachinin g technique were studied to fabricate the electrical devices on silico n wafer such as cantilever beam accelerometers and uncooled IR-detecto rs. In recent, a short problem of the PZT film deposited by metalorgan ic 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 studie d to investigate the influence of device etching processes on the fina l device characteristics. The remanent polarization values (at 15 V) o f the PZT film on the Pt/Ti without processes and with processes are a round 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 b e suggested. Piezoelectric coefficient (at 4 V) measured by single bea m 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/R u and Pt/RuO2 had almost the same remanent polarization and piezoelect ric 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.