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A Novel MOS-Channel Diode Embedded in a SiC Superjunction MOSFET for Enhanced Switching Performance and Superior Short Circuit Ruggedness

초록/요약 도움말

In this study, a novel MOS-channel diode embedded in a SiC superjunction MOSFET (MCD SJ-MOSFET) is proposed and analyzed by means of numerical TCAD simulations. Owing to the electric field shielding effect of the P+ body and the P-pillar, the channel diode oxide thickness (t(co)) of MCD can be set to very thin while achieving a low maximum oxide electric field (E-MOX) under 3 MV/cm. Therefore, the turn-on voltage (V-F) of the proposed structure was 1.43 V, deactivating the parasitic PIN body diode. Compared with the SJ-MOSFET, the reverse recovery time (t(rr)) and the reverse recovery charge (Q(rr)) were improved by 43% and 59%, respectively. Although there is a slight increase in specific on-resistance (R-ON), the MCD SJ-MOSFET shows very low input capacitance (C-ISS) and gate to drain capacitance (C-GD) due to the reduced active gate. Therefore, significantly improved figures of merit R-ON x C-GD by a factor of 4.3 are achieved compared to SJ-MOSFET. As a result, the proposed structure reduced the switching time as well as the switching energy loss (E-SW). Moreover, electro-thermal simulation results show that the MCD SJ-MOSFET has a short circuit withstand time (t(SC)) more than twice that of the SJ-MOSFET at various DC bus voltages (400 and 600 V).

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