Spider Web-Shaped Phononic Crystals for Quality Factor Improvement of Piezoelectric-on-Silicon MEMS resonators

This paper shows the approach to significantly reduce the energy dissipation of thin-film piezoelectric-on-silicon (TPoS) micro-electro-mechanical systems (MEMS) resonator by employing a 2D innovative lightweight spider web-shape phononic crystals (PnC) structure. An AlN-on-Si MEMS resonator, which is working at 40 MHz 5th-order width-extensional (WE) resonant mode, is selected to investigate the energy dissipation reduction by the proposed PnC. According to the simulation results, the proposed PnC structure shows a complete acoustic bandgap from 37 MHz to 44 MHz and can significantly reduce the energy loss. Moreover, the anchor loss (Qanc) of the resonator reached 2,090,000 at 40.03 MHz.