Material optimization for Capacitive pressure sensor- A COMSOL study

Choosing engineering materials for building specific machines and devices like transistors, pressure sensors and capacitors is a very crucial step. As the materials vary, the way these devices work and give results also varies. The progress of sensor technology contributed changes in the technical world, for example, in the medical field it is used in applications like pressure sensor for recognizing the pattern of sleep, blood pressure sensing, etc. Capacitive pressure sensors can be used to measure gas or liquid pressure in jet engines, vehicle tyres, keyboard switches, etc. Capacitive pressure sensors have more advantages compared to piezoresistive pressure sensors when it comes to power consumption, stability, packaging and sensitivity to temperature. The use of capacitive pressure sensors in various applications is increasing, so it is indispensable to study the technological development and further probabilities of capacitive pressure sensors. This paper presents a material selection case study through which we will be selecting a material for an optimized design of Micro Electro Mechanical Systems capacitive pressure sensor. In this paper, the capacitive pressure sensor is simulated by three materials namely Aluminum Nitride (AIN), Aluminum Oxide (Al
2
0
3
) and Graphene. This includes the diaphragm displacement vs Pressure and capacitance vs Pressure analysis where all the three materials are compared and the results are consolidated. Under 25KPa external pressure the diaphragm displacement and the capacitance are plotted using COMSOL Multiphysics software. The sensitivities, temperature dependence and the diaphragm displacement of the three materials are plotted thereby optimizing the best material.