Triple-order Optimization for Performance Enhancement of Piezoelectric MEMS Resonator

Quality factor (Q) is an extremely important parameter for the practical applications of micro-electromechanical systems (MEMS) resonators. Single optimization is difficult to achieve the high-performance MEMS resonators. This paper reports a strategy of triple-order optimization for high-performance piezoelectric MEMS resonator by resonant body parallel connection, suspended frame structure and phononic crystals (PnC). Firstly, according to the Butterworth Van Dyke (BVD) equivalent circuit model, the topologies structure of resonator was comprehensively studied and the three resonant bodies parallel connection was proposed to lower the motional impedances, while the anchor loss will rise due to the number of tethers increased. Secondly, the suspended frame structure was utilized to reduce the number of tethers in parallel-type resonators to suppress the anchor loss. Thirdly, the PnC structure was proposed to further realize high-Q by preventing the leakage of acoustic energy from resonant body to substrate via tethers. Finally, the Q of the proposed resonator was obtained by using finite-element-analysis (FEA) simulation, which revealed a 3.3fold enhancement (i.e. Q u = 9318.0) compared with the conventional resonator (i.e. Q u = 2799.6). In the meantime, the motional resistance and insert loss have also been significantly optimized.