High-Temperature Piezoresistance of Silicon Carbide and Gallium Nitride Materials

We examine the temperature dependence of the piezoresistive coefficients of silicon carbide (SiC) and gallium nitride (GaN) crystals, which are prospective materials for high-temperature applications owing to their wide-bandgap properties. The temperature-dependent piezoresistive coefficients of these materials were obtained by modeling experimental resistance changes using thermomechanical numerical simulations. This work reports the piezoresistive coefficients of 4H-SiC and GaN at the high-temperature environments, which are still not well researched. The results revealed that the temperature dependences of piezoresistive coefficients were strongly related to the ionization energy, and a high ionization energy stabilized the values of the piezoresistive coefficients at high temperatures. Our proposed temperature modeling method helps in predicting the temperature dependence of the piezoresistive coefficient using the value at the room temperature and the ionization energy of the material, which is useful for evaluating the piezoresistive effect at different temperatures during device simulations.