I. Introduction
Due to the superior material and device properties, SiC MOSFETs have become one of the most promising power switches for high-performance power electronic systems [1], [2], [3]. Nowadays, SiC MOSFETs not only have already been widely adopted in electric vehicles (EVs) and photovoltaic inverters but also are increasingly gaining attention from the aerospace industry [4]. However, irradiation reliability is still in the way of adopting them in space applications because the incident irradiation could gradually degrade the power devices’ electrical parameters or even destroy them instantaneously. Total ionizing dose (TID) effect is one of the most important types of space irradiation, and extensive research concerned with the irradiation effect on SiC MOSFETs has been reported so far. For example, Akturk et al. [5] experimentally verified that even those unhardened commercial SiC MOSFETs have an irradiation resistance of >100 krad. Many individual studies have also been conducted to explore the mechanisms of the irradiation-induced degradation in MOS structure in detail, and a common understanding that the accumulation of positive charges and interface traps in gate oxide causes the degradation has been achieved [6], [7], [8], [9]. Based on the fundamental understanding, Nicole [10] quantitively modeled the TID reliability effect in SiO2 layers, and Sanchez et al. [11] proposed a physics-based model incorporating TID and aging effect for MOS technologies by calculating surface potential to capture the charge contribution. Though these physical models further help understand the basic mechanisms, they are hardly suitable for predicting the degradation and/or lifetime of SiC MOSFETs after irradiation. In addition, it should be noted that almost all reported irradiation experiments focused on gate bias conditions, and seldom investigation under drain bias condition has been reported yet. Consequently, there is lacking a comprehensive model that can predict irradiation-induced degradation of SiC MOSFETs for switching-mode applications, which hinders the adoption of SiC MOSFETs into practical space applications.