An accurate nonlinear temperature-dependent analytical model of the drain-source turn-on current changing rate for SiC MOSFETs

The thermal sensitive electrical parameter (TSEP) junction temperature estimating method is an important way to enhance the reliability of SiC MOSFETs, with the temperature-dependent model (TDM) serving as the fundamental basis. The drain-source turn-on current changing rate σds,on is a crucial TSEP, as it governs the turn-on characteristics and other associated transients TSEPs. However, the existing TDMs for σds,on are inaccurate and lack analytical rigor, thereby impeding the calibration process and limiting method generalization. To address this issue, we have developed an accurate nonlinear temperature-dependent analytical model (TDAM) for σds,on based on the gate turn-on transient model proposed in our previous study. First, the mechanism of carrier scattering is analyzed to determine the theoretical relationship between the mobility and the junction temperature. Furthermore, the relationship between the gate threshold voltage and the junction temperature is examined based on the principles of energy band theory. Third, the TDAM is established according to the obtained theoretical results. The proposed model is verified by the dual pulse experiment. Compared with existing models, it is more accurate and analytical, displaying the nonlinearity characteristics. The proposed model can pave the way for advancing transient TSEP methods and switching loss optimization strategies.