A Piezoelectric MEMS Resonant Temperature Sensor with 10-μk Resolution and 0.06-PJK2 Resolution FOM

This paper reports a new MEMS temperature sensor based on piezoelectric membrane resonator for temperature measurement and compensation applications. For the first time, it theoretically analyzed and experimentally validated that the main factor of temperature coefficient of frequency (TCF) is the difference in coefficient of thermal expansion (CTE) between the resonating structure and silicon substrate. The engineered temperature sensor achieved a TCF, i.e. sensor sensitivity, as high as -660 ppm/℃. Because of the high sensitivity and low noise oscillating circuit, the sensor reached an extremely high temperature resolution of 10 μK which is the best among state-of-the-art MEMS resonant temperature sensors; and the sensor also reached a superior resolution FoM of 0.06 pJK². In addition, the MEMS resonator operates at atmosphere pressure without vacuum packaging, and the cost-effective solution should have better reliability and long-time drift.