Investigation of silicon carbide (SiC) mosfet s short-circuit (SC) degradation mechanism is critical to improve the overall reliability of power converters. At present, research on the SiC mosfet s degradation mechanism mainly focuses on the on -state phase of the SC period. While, ruggedness of SiC mosfet s in the off -state phase of short-circuit tests (SCTs) were neglected. In this article, SiC mosfet s degradation mechanism in the off -state phase of SCTs are investigated comprehensively. Specifically, distribution and magnitude of electrothermal stress of devices under test in the off -state phase of SCTs are analyzed by technology computer aided design (TCAD) simulation, which reveals two important phenomena: 1) the device will suffer from long-term high temperature and high electric field stress in the off -state phase when negative turn- off gate voltage ( V _gs-off ) is applied; 2) high hole current in the channel region will last for several microseconds after the device is turned off . The observed SiC mosfet s degradation in the off -state phase of SCTs is then proved by experiments, through which, the excessively low V _gs-off can reduce the SC capability of SiC mosfet s is concluded. Moreover, the degradation results of static parameters of SiC mosfet s are presented and the degradation mechanism is analyzed in detail.

中文翻译：

---

短路条件下 SiC MOSFET 的断态应力退化研究

碳化硅（SiC）的研究mosfet 的短路 (SC) 退化机制对于提高电源转换器的整体可靠性至关重要。目前，SiC 的研究mosfet 的退化机制主要集中在SC 期间的导通阶段。同时，SiC 的坚固性mosfet s 在忽略了短路测试 (SCT) 的断态阶段。在这篇文章中，碳化硅mosfet 的退化机制全面研究了 SCT 的非状态阶段。具体来说，被测器件的电热应力分布和大小通过技术计算机辅助设计（TCAD）仿真分析SCTs的断态阶段，揭示了两个重要现象：1）器件在工作过程中会遭受长期的高温和高电场应力。断态阶段，当负转 关断栅极电压（ V _{gs- off} )被应用；2）器件开启后沟道区的高空穴电流会持续几微秒离开 。观察到的碳化硅mosfet 的退化然后通过实验证明了 SCT 的关态阶段，通过该实验，过低的V _{gs- off}会降低 SiC 的 SC 能力mosfet s 结束。此外，SiC静态参数的退化结果介绍了 mosfet 并详细分析了退化机制。