Theoretical analysis of on-state performance limit of 4H-SiC IGBT in field-stop technology

In this paper, the on-state performance limits of 4H-SiC IGBTs are theoretically estimated for the first time and compared against silicon counterparts. The theoretical analysis is based on the static modelling of a high-current PiN diode and the calculation results are examined with TCAD simulations. Owing to conductivity modulation effect, the on-state losses of 4H-SiC IGBTs do not show any significant increase with the increase in breakdown voltage. However, the large built-in potential of SiC poses an inherent limit on the reduction of on-state voltage drop. Compared with 4H-SiC IGBTs, the silicon based IGBTs exhibit superior on-state performance limits within the breakdown voltage range considered, although their drift layer thicknesses are 10 times higher than that of 4H-SiC IGBTs. Therefore, silicon IGBTs remain as efficient technologies for enhancing high power conversion efficiency.