Integration of an RF MEMS resonator with a bulk CMOS process using a low-temperature and dry-release fabrication method

In this paper, a novel low-temperature post-CMOS process to fabricate a microelectromechanical ( MEMS) bridge resonator has been developed. The integration of the MEMS resonator with the bulk N-well CMOS process is demonstrated experimentally. The sub-micron gap between the resonator beam and electrodes is defined by the sacrificial polymeric layer thickness and dry released in O-2 plasma. The resonator beam is fabricated using single crystal silicon and released using isotropic silicon etch. The effect of floating driving electrodes on the resonator operation has been analyzed and modeled. S-parameter measurement is conducted. Results show a resonant frequency of 64.56 MHz with a quality factor of 60 under atmospheric pressure for a resonator device with the length of 30 mu m, width of 4 mu m and thickness of 2 mu m operating at second resonant mode.