Design and optimization of a novel structural MEMS piezoresistive pressure sensor

A novel structural piezoresistive pressure sensor with four-beams-structured membrane has been proposed for low pressure measurements of less than 5 kPa based on silicon substrate. The model design, dimension calculation, and optimization process of the novel membrane structure are presented. The finite element method (FEM) has been used to analyze the stress distribution of sensitive elements and the deflection of the membrane. On the basis of data obtained from simulations, the proposed sensor achieves the best overall performance compared with other traditional membrane types. Moreover, the performance of the sensor has been further improved through optimizing its geometrical dimensions. The reasons why the proposed sensor can obtain high sensitivity and low nonlinearity error are also discussed in this paper. By localizing more strain energy in the SCRs and reducing the deflection of the membrane, the proposed sensor has achieved a high sensitivity of 25.48 mV/kPa and a low nonlinearity error of 0.75% FSS. Because of its good performance, the proposed membrane structure is a proper choice for the pressure measurement less than 5 kPa.