摘要
In this work, we present a novel microelectromechanical systems (MEMS) temperature sensor based on an aluminum nitride (AlN) overmoded bulk acoustic wave resonator (OBAR). Utilizing the overmoded operation of a AlN bulk acoustic wave resonator with a thick metal electrode, a large temperature coefficient of frequency (TCF) of -105 ppm/°C is achieved, while maintaining a high quality factor (Q) of 300 and an electromechanical coupling coefficient (kt2) of 4.34% at 3.98 GHz. This TCF is approximately 4.5X higher than that of a regular AlN thin-film bulk acoustic wave resonator (FBAR). Furthermore, based on the dual-oscillator beat frequency sensing topology using OBAR and FBAR resonators characterized in this study, a large TCFbeat of - 1,088 ppm/°C is obtained through theoretical predictions. © 2025 IEEE.
