Experimental Validation of Tuning Mechanisms Applied on AIN Piezoelectric Contour Mode MEMS Resonators

This paper presents finite element simulation and experimental results for a 60 MHz contour-mode piezoelectric MEMS resonator. The device which operates at the 5th order lateral bulk modal frequency was fabricated using the PiezoMUMPs MPW process which consists of a $0.5 \mu \mathrm{m}$ AlN layer over an SOI structure having a thickness of $10 \mu \mathrm{m}$. The simulated and experimental values for the quality factor are 2,824 and 3,153 respectively, which compare favorably with similar contour mode resonator designs employing AlN as a piezoelectric material. The effect of temperature on the resonant frequency and the quality factor has been analyzed in detail. The viability of implementing thermal and voltage tuning techniques has been investigated and a comparison of results is presented. Experimental results indicate a frequency variation of 162 kHz over a temperature range of 278-358 K for thermal tuning, while a frequency variation of 30 kHz is obtained over a voltage range of 9 V in the case of voltage tuning.