Understanding vibrant behavior of Si-circular diaphragm for low-pressure measurement

Abstract

Enhanced sensitivity, precise measurements and accuracy are the key factors to identify the performance of any sensor. In this paper, p-polycrystalline silicon micro-pressure sensor has been designed which works on the principle of piezoresistive effect. A theoretical modeling and computational simulation of the circular Si-diaphragm have been performed through the extensive study of stress and frequency response with the help of finite element method (FEM) within the framework of COMSOL. For a thin diaphragm (∼50 μm), the Eigen frequency and the frequency generated in a diaphragm under the influence of pressure has been optimized within the pressure range from 1-25 kPa. The modes of vibrations generated in the diaphragm have been optimized at wide-frequency range ∼200-800 kHz at various pressure values. The findings of the presented research have suggested that for a ∼50 μm thin diaphragm, the optimized fundamental frequency is ∼310 kHz for showing better piezoresistive response which results into enhanced sensitivity. Moreover, the simulation results show that for the designed sensor, the pressure sensitivity of ∼11.51 mv/psi has been conveyed.