MEMS Resonant Temperature Sensing with Variable Coupling Stiffness and Improved Sensitivity

This paper reports the sensitivity improvement of a double-ended tuning fork resonant thermal strain sensor operating close to buckling limit with electrostatic softening and electrostatic coupling. A decrease in the coupling stiffness pulls the resonance frequency of out-of-phase mode close to buckling, enhancing the sensitivity of the sensor. The sensitivities of the sensor for 0V proof mass voltage difference is 28.022 Hz/K while 100V proof mass voltage difference results in 33.945 Hz/K, with a 21% improvement.