On Tuning the Sensitivity of Thermal Piezoresistive Resonators by a DC Thermal Pumping Scheme

This work demonstrates tunable frequency sensitivity in a piezoresistive resonator through a DC thermal pump scheme. The piezoresistive resonator is a dual clamped-clamped beam, actuated capacitively and detected piezo-resistively (CAPD). By applying an additional DC thermal voltage, a thermal perturbation stiffness is introduced due to the intrinsic resistance difference between the piezoresistive beams. The stiffness alters the mechanical stiffness of the CAPD resonator, enhancing its frequency sensitivity. Experimental results show that the application of the DC thermal pumping voltage increases the frequency sensitivity by 1.8 times compared to its intrinsic frequency sensitivity.