Design and fabrication of SCS (single crystalline silicon) RF MEMS switch using SiOG process

In this paper, single crystalline silicon(SCS) RF MEMS switch for obtaining higher productivity and uniform characteristics compared with conventional metal switch, was designed and fabricated using SiOG(silicon on glass) process. The characteristics of the fabricated silicon switch were tested. By using SiOG substrate instead of a SOI substrate, fabrication cost can be significantly reduced. The proposed switch is fabricated on CPW(coplanar waveguide) and actuated by electrostatic force. Measured pull-in voltage was 19 V and 18 samples of measurable 20 samples showed variations less than 15% on average value of the measured voltages. Forming damping holes on the upper electrode led to a relatively fast switching speed. Measured ON and OFF time were 25 μs and 13 μs, respectively. After 10⁸ cycles repeated actuation, stiction problem was not occurred. But contact resistance was changed with about 0.5 to 1 ohm. The RF characteristics of the fabricated switch with 0 to 30 GHz are measured. The isolation and insertion loss measured on the 4 samples were -38 dB to -39 dB and -0.18 dB to -0.2 dB at 2 GHz, respectively.