Phononic Crystal for Enhancement of MEMS Resonator Quality Factor

This paper introduces a new phononic crystal shape for the quality factor enhancement of the thin-film piezoelectric-on-silicon (TPoS) MEMS resonators. The proposed phononic crystal creates an exceptionally broad acoustic band gap, effectively preventing energy leakage from the resonator to the anchors through supporting structures. This design leads to a substantial increase in the resonator's quality factor. The simulation results demonstrate that the Curved-box phononic crystal (CBX-PnC) produces a band gap extending up to 95 MHz, with a band gap percentage of 88%. Moreover, it enhances the unloaded quality factor from 20,000 to 27,000 and the anchor quality factor from 520,000 to 1,200,000. These enhancements represent a 2.3-fold improvement in the anchor quality factor and a 1.35-fold improvement in the unloaded quality factor.