Nonlinear piezoresistive effect of 4H–SiC for applications of high temperature pressure sensors

4H–SiC is an ideal material for micro-electromechanical system sensors used in high temperature environment due to its outstanding material properties. In this work, we systematically studied the piezoresistive characteristics of 4H–SiC with different doping concentrations in the range of 25–600 °C. We found that the piezoresistive curves of 4H–SiC with different doping concentrations show clear nonlinear fluctuations ranging from 494 to 600 °C. Moreover, as the doping concentration increases, the critical temperature point of the fluctuations gradually shifts towards higher temperature. Based on the analysis of the charge carrier transport mechanism, we found that the intrinsic excitation of 4H–SiC at high temperature can lead to nonlinear fluctuations in the piezoresistive effect, and proposed a theoretical model of piezoresistive coefficient GF of 4H–SiC under intrinsic excitation. Furthermore, the results of the variable temperature Hall effect test show that increasing the doping concentration of 4H–SiC can effectively suppress the nonlinear piezoresistive effect caused by intrinsic excitation. Based on the above investigation, we conclude that the appropriate doping concentration of 4H–SiC should range from 10 18 to 10 19 cm −3 , which provides important reference for the selection and design of 4H–SiC chip parameters. Graphical abstract