Sensitivity Analysis of MEMS-based Piezoresistive Pressure Sensor Implementing Ritz Method

Piezoresistive Pressure Sensor (PPS) using four Polysilicon piezoresistors on Silicon Nitride diaphragm is proposed in this paper. Sensing is accomplished via deposited polysilicon resistors. The analytical model of PPS is optimized with different aspect ratios (both square and rectangular). The performance parameters like largest deflection and highest induced stress on the diaphragm are analyzed in ANSYS and MATLAB. The analysis shows that the deflection and induced stress are maximum when the aspect ratio is minimum. The piezoresistors are symmetrically placed 65 $\mu$m from the boundaries of the diaphragm to achieve the highest sensitivity. The study also indicates that the sensitivity of the diaphragm based square sensor is greater than that of the rectangular one.