A High-Resolution Mass Sensor Based on Two Thermal Piezoresistive Self-Sustained Resonators Coupled via An Arching Membrane

This paper reports a mode-localized mass sensor based on two thermal-piezoresistive self-sustained resonators coupled by an arching mechanical membrane coupler. Sensitivities of the mass sensors based on coupled resonators with amplitude ratio readout depends on a low coupling factor. To lower the coupling stiffness between the two thermal-piezoresistive coupling resonators, an arching membrane coupler with thickness between 1 µm to 8 µm was fabricated underneath the coupling area of the two resonators, based on the aspect ratio dependent etching (ARDE) effect. The experimental results indicated that the sensitivity and resolution of the newly designed mass sensor with the arching membrane coupler were increased by 20 and 10 times, respectively, compared to the state-of-the-art.