Comprehensive assessment of MEMS double touch mode capacitive pressure sensor on utilization of SiC film as primary sensing element: Mathematical modelling and numerical simulation

Abstract

Capacitive Pressure Sensors have consistently been an indispensable application of MEMS (Micro Electro Mechanical Systems) because of their utility and precision. Silicon has proven to be a dominant material in MEMS based sensor design but it is unfit for applications operating in harsh environmental conditions. Silicon Carbide is a justified replacement to Silicon in these conditions due to its solitary attribute of robustness and high temperature tolerance. This work introduces a Silicon Carbide and Aluminum Nitride based DTMCPS (Double Touch Mode Capacitive Pressure Sensor) with a substrate notch. Condensed yet exhaustive step by step mathematics of key performance parameters have been detailed for the sensor under study. This is done to provide a detailed understanding of the underlying physical and mathematical principles. It also aims to provide a fast analysis model for prototyping the sensor to bypass the need for bulky simulation software. A Finite Element Analysis (FEM) analysis for the design was conducted using COMSOL and the results agree with the mathematical model. It is evident from numerical simulation and the FEM analysis that the proposed sensor provides better performance than comparable designs reported in literature.