Abstract
We have developed piezoelectric RF-MEMS switch using PZT thin films for low-voltage actuation. PZT thin films with composition of Zr/Ti=53/47 were grown on the (111) Pt/Ti/Si substrates by RF-sputtering. The cantilever type actuators composed of PZT thin films and Cr elastic layers were successively fabricated as unimorph structure, but large initial bending arises because of residual stress in the PZT and Cr layers. We optimized the design of the actuators to satisfy flat structure as well as large deflection, and we adopted X type connectors in the middle of the beam. According to FEM simulation (MARC2005) results, the deflection of the optimized actuators composed X type connectors was as high as 3.2μm at a relatively small voltage of 5V. Their resonant frequency was 14.6kHz and larger than cantilever type actuator's one. However, the deflection of the actuators was as high as 400nm at 5V, and the actuators geometry cause the degradation of the deflection characteristic.
