High resolution microresonator-based digital temperature sensor

A digital temperature sensing technique using a complementary metal oxide semiconductor (CMOS) compatible encapsulated microresonator is presented. This technique leverages our ability to select the temperature dependence of the resonant frequency for micromechanical silicon resonators by adjusting the relative thickness of a SiO2 compensating layer. A dual-resonator design is described that includes a pair of resonators with differential temperature compensations so that the difference between the two resonant frequencies is a sensitive function of temperature. The authors demonstrate a temperature resolution of approximately 0.008 degrees C for 1 s averaging time, which is better than that of the best CMOS temperature sensors available today. (C) 2007 American Institute of Physics.