Single-event burnout and single-event leakage current (SELC) in silicon carbide (SiC) power devices induced by heavy ions severely limit their space application, and the underlying mechanism is still unclear. One fundamental problem is lack of high-resolution characterization of radiation damage in the irradiated SiC power devices, which is a crucial indicator of the related mechanism. In this Letter, high-resolution transmission electron microscopy (TEM) was used to characterize the radiation damage in the 1437.6 MeV 181Ta-irradiated SiC junction barrier Schottky diode under 200 V. The amorphous radiation damage with about 52 nm in diameter and 121 nm in length at the Schottky metal (Ti)–semiconductor (SiC) interface was observed. More importantly, in the damage site the atomic mixing of Ti, Si, and C was identified by electron energy loss spectroscopy and high-angle annular dark-field scanning TEM. It indicates that the melting of the Ti–SiC interface induced by localized Joule's heating is responsible for the amorphization and the possible formation of titanium silicide, titanium carbide, or ternary phases. The mushroom-like hillock in the Ti layer can be attributed to Rayleigh–Taylor instability, as another evidence for ever-happened localized melting near the Schottky interface. These modifications at nanoscale in turn cause localized degradation of the Schottky contact, resulting in permanent increase in leakage current. This experimental study provides very valuable clues for a thorough understanding of the SELC mechanism in SiC diodes.

中文翻译：

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揭示 SiC 肖特基二极管在 200 V 重离子辐照后漏电流退化的微观结构损伤


重离子引起的碳化硅（SiC）功率器件中的单粒子烧毁和单粒子漏电流（SELC）严重限制了其空间应用，且其潜在机制仍不清楚。一个根本问题是缺乏对辐照碳化硅功率器件辐射损伤的高分辨率表征，而这是相关机制的关键指标。本文采用高分辨率透射电子显微镜（TEM）对1437.6 MeV、181Ta辐照的SiC结势垒肖特基二极管在200 V下的辐射损伤进行了表征。非晶辐射损伤的直径约为52 nm，尺寸为121 nm。观察了肖特基金属（Ti）-半导体（SiC）界面处的长度。更重要的是，在损伤部位，通过电子能量损失谱和高角度环形暗场扫描 TEM 识别出了 Ti、Si 和 C 的原子混合。这表明局部焦耳加热引起的 Ti-SiC 界面熔化是造成非晶化以及可能形成硅化钛、碳化钛或三元相的原因。 Ti 层中的蘑菇状小丘可归因于瑞利-泰勒不稳定性，这是肖特基界面附近经常发生局部熔化的另一个证据。这些纳米级的修改反过来会导致肖特基接触的局部退化，导致漏电流永久增加。这项实验研究为深入了解 SiC 二极管的 SELC 机制提供了非常有价值的线索。