Actuation Dependency of Frequency Tuning in MEMS Resonators

Abstract

This letter shows that active tuning of MEMS resonators through temperature is highly dependent on the actuation mechanism used, and demonstrates the adverse effects of using substrate conductive heating characterization results to predict device’s performance in their final application, where Joule heating is most likely to be used. A buckled VO2-based SiO2 tunable MEMS resonator is used in the study, where the thermal frequency stability or active tuning of the resonant frequency is thermally induced. The VO2 phase transition is triggered by substrate heating and Joule heating. When using Joule heating, the increasing strain energy during the phase transition results in a monotonic increase in resonant frequency, with a maximum resonant frequency shift of 11.9%. For substrate heating, the resonant frequency shift is non-monotonic and shows a 10.6% increase followed by a 7.8% decrease. The different frequency shift patterns that are observed for two heating mechanisms can be attributed to different stress-strain responses. [2019-0256]