An Improved SPICE Model of SiC MOSFET by Output Nonlinear Capacitor Optimization

Simulating the characteristics of SiC MOSFET is of crucial importance to its application. Due to the fast switching speed of SiC MOSFET, accurate modeling of the terminal capacitances is required. In most existing SiC MOSFET models, the drain-source capacitance is considered meticulously, but it is generally modeled by a junction capacitance of the SiC MOSFET body diode, which would lead to simulation errors. Moreover, most of those models are developed from the data provided in the datasheet. In this paper, an improved SiC MOSFET SPICE model is proposed. The static characteristics and terminal capacitances of the SiC MOSFET from Wolfspeed C2M0080120D are measured for the proposed model. Based on the Enz-Krummenacher-Vittoz (EKV) model, the proposed model utilizes the self-defined channel current to describe the static characteristics, which can simplify the parameter extraction process and reduce the risk of non-convergence. In addition, the drain-source capacitance is studied in detail, an auxiliary capacitance is used for better capacitance fitting and there, an accurate spice model is established. A double pulse test platform is built to test the device. The comparison between simulation and experimental results verified that the improved model is more accurate than previous models.