Characteristic Analysis of a Square Diaphragm Capacitive Pressure Sensor with Linkage Film

Abstract

Capacitive pressure sensors (CPSs) have become more prevalent compared to the piezoresistive pressure sensors because they generate superior sensitivity and better linearity for the same application. Due to the innumerable use cases of the CPSs, it is becoming increasingly critical to carry out efficient analysis for their modeling. The higher sensitivity of a square diaphragm for the same side length in comparison to a circular diaphragm makes it ideal for sensor design. In this work, a complete formulation for analysis of a CPS with a square diaphragm having a linkage film has been presented. A comprehensive study of sensor parameters like capacitance, deflection of the diaphragms, capacitive and mechanical sensitivity has been formulated to aid the choice of sensor characteristics. This work also focuses on the method to determine the fundamental design parameters for optimal operation. Complex and resource-expensive methods have been used in the past for the analysis of MEMS capacitive pressure sensors. MATLAB and ANSYS have been used to compute and simulate the results.