Temperature Characteristics of 4H-SiC Substrate and Thin-Film Resistor Applied in MEMS Piezoresistive Sensors

Silicon carbide (SiC) is currently the preferred material for micro-electromechanical system (MEMS) sensors used in extreme environments and it has been applied in many high-temperature piezoresistive sensors. However, there has been a lack of accumulated data and references for research on the characteristics of the 4H-SiC substrate and thin-film resistors used in high-temperature environments. Consequently, the effect of temperature on the sensor in high-temperature environments cannot be evaluated in advance at the design stage. In this study, the mechanical characteristics of a 4H-SiC substrate and the thin-film resistor resistivity were examined based on the temperature error model of a typical MEMS piezoresistive sensor and the temperature function models were established, which could be used to analyze the temperature effect of the sensors under high temperature conditions. All the test data were integrated into a typical physical chip including a 4H-SiC substrate and thin-film resistors. The simulation results of the device exhibited a high consistency with the test results, the largest average error being only 4.53%, verifying the correctness and validity of the test data. This study proposed the data models for the temperature characteristics of 4H-SiC materials, providing powerful support for the design and development of high-temperature MEMS sensors.