| Electromechanical resonators have formed the basis of telecommunication circuits for decades through the use of quartz crystal oscillators. Recently, MEMS resonators-based oscillators have become a possible replacement in selective applications for quartz crystal oscillators. The focus of this work is to show the performance of micromachined thin-film piezoelectric-on-silicon resonators can be improved through the design of the substrate-tether interaction. In lower frequency devices, resonators exhibit a significant increase to quality factors through the application of acoustic reflectors etched into the surrounding substrate. Simulation shows that the acoustic reflectors can limit the anchor loss for these devices and experimental results confirm efficacy. For higher frequency resonators, multiple tethers show greater quality factors, lower motional impedance, and improved power handling capabilities. |
