Simulation Study of Carbon Vacancy Trapping Effect on Low Power 4H-SiC MOSFET Performance

The carbon vacancy in 4H-SiC is an important recombination center of the minority carrier and a direct consequence of SiC-based device degradation. In 4H-SiC, this defect acts as the primary carrier-lifetime killer. Whether, low-energy electron radiation exposure or high temperature processing in an inert ambient gas will produce the carbon vacancy defect. Despite, the extensiveness of the studies concerning the defect’s modeling and characterization, numerous essential questions remain. Amongst them, we have the impact of these defects on the performance of 4H-SiC MOSFET. Herein, the influence of intrinsic defect states, namely, Z1/2 and EH6/7 centers, on the 4H-SiC MOSFET electrical outputs is examined via 2D numerical simulation. The obtained results show that the traps act to increase the device on-state resistance (RON), reduce the channel mobility, increase the threshold voltage (Vth). Besides, the increase of the temperature leads to less influence of the traps on the threshold variation. Furthermore, due to their locations in the bandgap, the impact of both Z1/2 and EH6/7 centers at room temperature on the device electrical outputs is extreme. For high temperature the EH6/7 have the severest impact because of the cross section temperature dependency.