High-frequency high-Q micro-mechanical resonators in thick epipoly technology with post-process gap adjustment

This paper presents high-Q high-frequency lateral-mode clamped-clamped beam micro-resonators driven by parallel-plate electrostatic transducers fabricated in a thick epipoly micromachining technology. An innovative approach is employed to reduce an intrinsically high transducer gap value of more then 3.0 /spl mu/m (determined by the need of 15 /spl mu/m thickness structural layer etching) down to 0.2-0.4 /spl mu/m after the fabrication. This is achieved by employing an electrostatic motor that approaches actuating and sensing electrodes close to the resonator. The electrode motor is driven with 30 V DC voltage, without any DC current consumption. Two resonators having a resonance frequency of 10 MHz have been fabricated with gap values of respectively 0.2 and 0.4 /spl mu/m. A comparative analysis of performances of the two resonators is given in the paper.