Abstract:

By using LPCVD SiO₂ and poly silicon as sacrificial layer and cantilever respectively, a poly silicon micromachined RF MEMS (radio frequency microelectronic mechanical system) switch is fabricated. During the fabrication process, the stress of poly-silicon is released to prevent poly-silicon membrane from bending, and the issue of compatibility between RF switch and IC process technology is also resolved. The low residual tensile stress poly-silicon cantilever is obtained by the optimization. The switch is tested, and the preliminary test results show: the pull down voltage is 89 V, and the switch speed is about 5 μs. The switch provides the potential to build a new fully monolithic integrated RF MEMS for radar and communications applications.

Key words: poly-silicon micromachined switch, cantilever, sacrificial layer, restoring force