Design, realization and testing of micro-mechanical resonators in thick-film silicon technology with postprocess electrode-to-resonator gap reduction

This paper presents the design, fabrication and testing of high-Q high-frequency lateral-mode clamped-clamped beam micro-resonators driven by parallel-plate electrostatic transducers fabricated in a thick epipoly technology. An innovative approach is employed to reduce an intrinsically high transducer gap value (>3.0 mum) required by the need of 15 mum thick structural layer etching down to 0.2-0.4 mum after the fabrication. This is achieved by employing an electrostatic motor that approaches the 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 0.2 and 0.4 mum respectively. A comparative analysis of performances of the two resonators is given in the paper.