SiC Capacitive Pressure Sensor Node for Harsh Industrial Environment

Abstract

This paper presents an analytical and simulation solution for MEMS (Microelectromechanical Systems) capacitive pressure sensor operating in harsh environment. The proposed sensor consists of a circular SiC (Silicon Carbide) diaphragm suspended over sealed cavity on a Si (Silicon) substrate. SiC is selected in this work due to its excellent electrical stability, mechanical robustness and chemical inertness properties, which is very adequate for harsh environment. The design is based on the use of COMSOL multiphysics structural analysis to design and obtain analytical solution for a circular diaphragm deflection. The proposed sensor demonstrated diaphragm of 100 µm diameter with the gap depth 0.64 µm and the sensor exhibit a linear response with pressure load up to 3.5 MPa with maximum deflection up to 0.52 µm. Keywords-COMSOL; harsh environment; high dielectric materials; silicon carbideI.

CMOS-compatible ruggedized high-temperature Lamb wave pressure sensor

“…Pressure sensors can be found in several harsh environment application areas, like automotive, aeronautic or oil-drilling industry [1][2][3][4][5][6][7][8][9][10]. Different approaches have been used to sense pressure at higher temperatures.…”

“…figure4. Material properties[32][33][34][35] and appropriate boundary conditions are summarized in tables 1 and 2 respectively.…”

High-performance Dual-band Wireless Capacitive Pressure Sensor

“…For the capacitive pressure sensor, several diaphragm materials such as Aluminum (Al) [6], Gold (Au) [7], Stainless Steel [8] and Silicon (Si) [9] are compared with SiC [4]. The maximum center deflection of the circular diaphragm, the capacitance of the pressure sensor under applying pressure loads up to 500 kPa, and maximum pressure load in normal mode of operation are summarized in table 1.…”

“…Compared to a square-or rectangular-shaped diaphragm, circular-geometry exhibits simplicity in design, low fabrication cost, improved sensitivity and less sensitive to temperature variations for the same effective area. The capacitive pressure sensor consists of an array of circular pressure sensitive diaphragms (sensing cells), which serve as the top electrodes [4]. The diaphragms are switched in parallel to increase the value of the capacitance.…”