Influence of N-drift Layer Parameters on Static and Dynamic Performances of Ultra-high Voltage SiC IGBT

The unique properties of SiC not only originally promise superior electrical performances of SiC power devices, but also offer more margins in power devices designing. For example, different combinations of doping concentration and thickness of N-drift layer of SiC IGBT can be used to block same high-voltage. However, in the optimization of N-drift layer, we typically only consider the maximum breakdown voltage and carrier lifetime related performances, and the influences of doping concentration and thickness of N-drift layer are usually ignored. In this paper, we comprehensively study their influences on both static and dynamic performances of 15kV SiC IGBT by TCAD simulations. It is found that a lower N-drift doping concentration can achieve better trade-off between VON and Eoff, and enlarge the RBSOA. Nevertheless, it also causes higher voltage slop (dv/dt) and current slop (di/dt), thus more electromagnetic interference (EMI) related issues. Therefore, it is necessary to reconsider optimizing N-drift layer for high-performance SiC IGBTs.