Sensitivity Analysis of MEMS Capacitive Pressure Sensor with Different Diaphragm Geometries for High Pressure Applications

Abstract

In this paper three MEMS capacitive pressure sensors with different diaphragm geometries are designed and simulated. The sensors modelled have square, circular and rectangular diaphragms, with some fixed area. The diaphragm thickness of the three sensors is 63μm. The sensors are designed for high pressure sensing, over a range of pressure varying from 1Mpa to 100Mpa. The paper presents a rectangular diaphragm designed using a golden ratio of rectangle design widely used in image processing application with the ratio (b/a) equal to 1.618. Silicon<100> is used as a diaphragm material, because of its excellent properties. The paper provides a thorough analysis and discussion on different performance parameters for capacitive pressure sensing, such as the total displacement, capacitance, PRCC (Percentage Relative Change in Capacitance), electrical sensitivity. The design and simulation of the pressure sensors have been done based on Finite Element Method using Multiphysics simulation platform. Such kind of pressure sensors can be used in harsh environments involving high pressure applications.