Low voltage actuated RF micromechanical switches fabricated using CMOS-MEMS technique

This study investigates the fabrication of radio frequency (RF) micromechanical switches with low actuation voltage using the commercial 0.35 mu m double polysilicon four metal (DPFM) complementary metal oxide semiconductor (CMOS) process and the post-process. The advantages of RF micromechanical switches include low pull-down voltage and ease of post-processing. Three types of RF micromechanical switches are designed and manufactured. The RF switches are capacitive type, and the structures of the switches comprise coplanar waveguide (CPW) transmission lines, supported springs and a suspended membrane. The post-process requires only a wet etching silicon dioxide layer. Experimental results show that type-c switch needs only a pull-down voltage of 7 V.