The design and analysis of a novel structural piezoresistive pressure sensor for low pressure measurement

A micro electromechanical system piezoresistive pressure sensor with annularly grooved membrane combined with rood beam has been proposed for low pressure measurements based on silicon substrate. The model design, geometry analysis and performance prediction of the novel structure sensor are presented. Compared with other structural membranes, the proposed sensor achieves several advantages such as micro size, high sensitivity, low nonlinearity and stable dynamic behavior. Through analyzing the stress distribution of sensitive elements and the deflection of membrane by finite element method, the proposed structure can alleviate the contradiction between sensitivity and linearity to realize a device with high accuracy. The reasons why the proposed sensor can maximize sensitivity and minimize nonlinearity are also discussed. By localizing more strain energy in the high concentrated stress profile and creating partially stiffened membrane, the proposed sensor has achieved a high sensitivity of 34.5 mV/V/psi and a low nonlinearity of 0.25% FSS. Thus, the proposed structural sensor will be a better choice for low pressure applications less than 1 psi.