Modeling the temperature response of 4H silicon carbide junction field-effect transistors

The electrical characteristics of 4H-SiC depletion-mode junction field-effect transistors (JFETs) have been measured over an extended temperature range from 218 to 673 K. A basic model has been applied to predict I–V characteristics for SiC JFETs over this extended temperature range using the standard abrupt-junction long-channel JFET equations. The model employs a two-level donor ionization structure using ionization energies of 0.050 and 0.080 eV and assumes a two-step inverse power law dependence of mobility on temperature based on recently published Hall measurement data. The modeled I–V characteristics are in good agreement with the experimental data over the temperature range from 273 to 673 K. The deviations between the experimental data and the response model at the temperature extremes are attributed to increased substrate resistivity at 218 K and increased device leakage currents at 673 K.