4H-SiC MEMS Accelerometer with Integrated SiC-FET Readout for High Temperature Harsh Environment: Design and System-Level Simulation

In this paper, the design and simulation of a monolithically integrated silicon carbide (SiC) MEMS piezoresistive accelerometer with an on-chip SiC field-effect transistor (SiC-FET) readout circuit are presented for applications in harsh environments. The proposed device can be fully realized on a single SiC platform, ensuring robust operation at a very high temperature (1000 K) and removing the bottlenecks associated with heterogeneous integration and silicon-based sensor electronics. Finite-element-method (FEM) simulations were performed to investigate the mechanical performance of the accelerometer, including sensitivity, cross-axis response, resonant frequency, and thermal stability. The designed accelerometer exhibits a z-axis sensitivity of 35.8 Ω/g with low cross-axis sensitivities of 0.27% and 2.12% along the x- and y-axes, respectively. The eigen frequency analysis shows a fundamental resonance frequency of 1640 Hz and an operating bandwidth of 328 Hz. Thermal simulations indicate excellent stability performance from 300 K to 1000 K with resistance and displacement variations of less than 0.21% and 0.009%, respectively. A 4H-SiC MOSFET was designed and analyzed by the TCAD process and device simulations. It was shown to operate stably in a wide temperature range without breakdown. The FEM and TCAD results were incorporated into a Verilog-A model and implemented in Cadence Virtuoso to evaluate the complete sensor-readout system. The integrated SiC-FET common-source amplifier achieved a sensitivity of up to 100 mV/V at 1000 K with a non-linearity of approximately 1%. The results demonstrate the feasibility of a fully integrated all-SiC accelerometer platform for high-temperature sensing applications in aerospace, automotive, energy, and industrial environments.