A Deep Insight Into the Ionizing Radiation Effects and Mechanisms on the Dynamic Characteristics of SiC MOSFETs

The robustness of silicon carbide (SiC) metal–oxide–semiconductor field-effect transistor (MOSFET) under harsh environments is a crucial factor to ensure power conversion system safely and continuously operating. In this work, the degradation behaviors and mechanisms of switching characteristics after gamma-ray radiation were comprehensively investigated, presenting the link of atomic-scale defects to device properties behaviors. The changes in turn-on and turn-off characteristics after irradiation are recorded and first analyzed in terms of the capacitance and static parameters characterizations. The decrease of the threshold voltage (
${V}_{\text {th}}$
) plays a dominant role in the accelerated turn-on and delayed turn-off processes over the capacitance
${C}_{\text {GS}}$
. The trapped interface and oxide charge in SiC MOSFETs as a function of radiation dose are separated from the subthreshold characteristics, which are suggested to result in the
${V}_{\text {th}}$
shifts and
${C}_{\text {GS}}$
changes. Deep-level transient spectroscopy measurements were performed to investigate the involved interface defects during irradiation. It is suggested that the oxygen vacancy in the oxide and SiC/SiO2 interface defects locating from
${E}_{\text {C}} -0.2$
to
${E}_{\text {C}} -0.6$
eV act as hole and electron trapping centers during irradiation, respectively, and thus lead to the degradations of switching performances of SiC MOSFETs.