The Mechanical and Electrical Characteristics of a 3C-SIC for Mems Capacitive Pressure Sensor Diaphragm

Abstract

Silicon carbide (3C-SiC) is promising materials due to many desirable characteristics that make it an excellent material for the fabrication MEMS capacitive pressure sensor operate in harsh environment. The main novelty of this work involves the use of (3C-SiC) thin film as the flexible plate, which is anisotropically etch with fixed plate being bonded by a silicon substrate. The MEMS capacitive pressure sensor is simulated using COMSOL ver 4.3 for mechanical and electrical verification. This work compares the design of a diaphragm-based MEMS capacitive pressure sensor employing 3C-SiC and Si thin films operating at extreme temperature which is 1000°C. Both materials are designed with the same area, but with different thickness of diaphragm which is 1.0 µm, 1.6 µm and 2.2 µm. In this paper, we study the effects of pressure across the temperature, capacitance performances and the maximum Von Mises Stress simulation in the center of diaphragm element. We also compare the mechanical and electrical characteristics between two materials. The 3C-SiC thin film is far superior to Si thin film mechanically to withstand an applied pressure, temperature that affect the Von Mises Stress up to 148.32 MPa, the maximum output capacitance of 1.93 pF is achieved with less total energy of 5.87 x 10 J, -13 thus having a 50 % saving as compared to Si.