Ionization Radiation-Induced Reliability Degradation of SiC Power MOSFET

The long-term reliability of SiC power MOSFETs under total ionizing dose (TID) effects was investigated in this article. Time-dependent dielectric breakdown (TDDB) test showed that the degradation behavior of the gate leakage current is dependent on the bias voltage. At a critical gate bias of 43.5 V, the gate leakage current first increases and then decreases before oxide breakdown. In this case, the effects of hole trapping, interface trap depassivation, as well as electron trapping during Fowler–Nordheim (FN) tunneling occur sequentially within the oxide, as described by the composite model. After total dose radiation, the oxide breakdown time is markedly reduced, while the leakage current degradation pattern remains unchanged. This is attributed to radiation-induced oxide trapped charges and additional acceptor-type defects, which modulate the oxide electric field and alter the FN tunneling barrier.