On the sensitivity of bifurcation-based electrostatic MEMS sensors: cantilever with tip plate

An electrostatic bifurcation-based microcantilever sensor equipped with a tip plate is investigated for sensitivity. A closed-form expression for sensitivity of this type of sensors is approximated using the frequency-response equation of the cantilever. The expression relates the sensor sensitivity due to the added mass with its geometric and material properties. The formula shows that the sensitivity of the sensor is quadratically proportional to the quality factor. Further, the sensitivity is inversely proportional to the third power of the beam stiffness and the ninth power of the gap distance. This formulation unveils the factors influencing the sensitivity of this sensor class configuration and could serve as a guideline in optimizing the design of this type of sensors for enhanced performance.