​Abstract: This paper presents a design and simulation study of SiC-MEMS pressure sensors featuring an embedded peripheral MOSFET and an integrated current-mirror for high temperature applications. The proposed pressure sensor structures employ square and circular shaped strain sensing MOSFETs embedded on the periphery of square and circular SiC diaphragms, respectively. The MOSFETs are configured as a resistively loaded current mirror configuration. Pressure-induced strain is detected through the piezoresistive behaviour of 4H-SiC n-channel MOSFET devices. The mechanical and electrical behaviour of the proposed sensors was simulated using COMSOL Multiphysics and TSPICE software over pressure and temperature ranges of 0 – 10 MPa and 25 – 400 °C, respectively. The simulated pressure sensitivities for square and circular sensors were found to be 0.2 mV/MPa and 0.4 mV/MPa, respectively, at 25 °C which increased to 27.86 mV/MPa and 62.66 mV/MPa at 400 °C. The temperature sensitivities of proposed square and circular shaped pressure sensors were found to be 0.65 mV/ °C and 1.49 mV/ °C, respectively, at an applied pressure of 10 MPa. The simulation results underscore the critical role of channel geometry in improving sensor sensitivity, paving the way for robust 4H-SiC MOS-based pressure sensors for harsh environments.

Keywords: Silicon carbide, MOSFET, MEMS, Pressure sensor, Piezoresistivity, Current mirror, Diaphragms.

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