A Study on Short Circuit Characteristics of 4H-SiC MOSFET Coupled With Electron Irradiation

In this article, the electron irradiation coupling short circuit (SC) characteristics of 4H-silicon carbide (SiC) MOSFET are studied. The SC influence mechanism of electron irradiation coupling is proposed, and the influence of minority carrier lifetime on the SC characteristics of the device after irradiation is further studied. The 4H-SiC MOSFET and 4H-SiC wafer are irradiated by 2-MeV electrons. The changes in static parameters of 4H-SiC MOSFET are analyzed, and the SC characteristics of 4H-SiC MOSFET under electron irradiation coupling are studied by the limit SC (LSC) test method. The results show that after irradiation, the SC peak current of 4H-SiC MOSFET increases by 9.6%, the critical SC failure time ( ${t}_{\text {crit}}$ ) decreases by 10.85%, and the critical SC failure energy ( ${E}_{\text {crit}}$ ) decreases by 5.29%. MOSFET’s LSC failure mechanism after electron irradiation is parasitic BJT conduction. Through TCAD simulation and theoretical derivation, it is proved that the increase of the base current is the main cause of parasitic BJT conduction, and the decrease of carrier lifetime will trigger parasitic BJT conduction earlier. The minority carrier lifetime can be reduced by 97% after electron irradiation. The influence mechanism of electron irradiation on SC characteristics is verified by TCAD simulation. The total ion dose effect will increase the SC peak current, and the displacement effect will significantly reduce the minority carrier lifetime, thus reducing the SC capacity of the device. The simulation results are consistent with the experimental results.