Both experiments and simulations have shown that single-event burnout (SEB), a catastrophic event, occurs at less than half of the rated blocking voltage in commercial 4H-SiC power devices under a heavy-ion strike. The failure was shown to be due to significant impact ionization near the epi/substrate interface. Adding a buffer layer between the drift epi and substrate layers reduces the impact ionization effect and changes the thermal failure location. In this article, the SEB phenomenon in a 4H-SiC power MOSFET utilizing a buffer layer is investigated. Heavy-ion transport and 3-D electro-thermal transient simulations were performed to study the device response to a heavy-ion strike. In examining the time evolution of electric field profile, charge carrier dynamics, and thermal heat transfer, it is determined that the failure mode for this design is the location shift of the mesoplasma (or hot spot) to within the drift epi region, away from the high field area. A sensitivity analysis was conducted to identify the dominant electrical or thermal factors contributing to device failure due to second breakdown. From these simulations, it is found that the semiconductor thermal conductivity is the primary material parameter that influences the mesoplasma formation.

中文翻译：

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4H-SiC功率MOSFET器件中离子诱导的介晶形成和热破坏

实验和模拟均表明，在重离子撞击下，商用4H-SiC功率器件中，单事件烧断（SEB）是一种灾难性事件，发生在额定阻断电压的一半以下。证明该失败是由于外延/衬底界面附近的显着碰撞电离所致。在漂移外延层和衬底层之间添加缓冲层可降低碰撞电离效应并更改热失效位置。在本文中，研究了使用缓冲层的4H-SiC功率MOSFET中的SEB现象。进行了重离子迁移和3-D电热瞬态仿真，以研究器件对重离子撞击的响应。在检查电场分布，电荷载流子动力学和热传热的时间演变时，可以确定该设计的失败模式是中性粒子（或热点）向漂移Epi区域内远离高电场区域的位置偏移。进行了灵敏度分析，以确定导致二次故障导致设备故障的主要电气或热因素。从这些模拟中，发现半导体热导率是影响介晶形成的主要材料参数。