Power electronic devices for high-voltage applications prefer wide-bandgap semiconductors such as silicon carbide, whereas the immaturity of epitaxial growth technology introduces many extended defects, some of which are crucial to the electrical performance of fabricated devices. Therefore, it is much expected to find out some deep relation between extended defects and device performance. In this work, based on comparisons of breakdown behaviors of 4H-SiC power diodes with or without extended defects of different types, the importance of several features of the extended defect, including the distance, length, and orientation, is reported. Besides, based on the experimental results from dark-field microscopy, near-ultra-violet photoluminescence and topography, and theoretical analysis with numerical calculations, the mechanism of a particular asymmetric breakdown behavior in 4H-SiC devices along the step-flow direction is revealed, which originates from the prevalent step-controlled epitaxy technology for the commercial 4H-SiC epitaxial wafer. With the proposed result and understanding, it is possible to achieve a higher yield in production at a similar material cost.

中文翻译：

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了解沿阶梯流方向的位置具有扩展缺陷的 4H-SiC 功率二极管的击穿不对称性

用于高压应用的电力电子器件更喜欢碳化硅等宽带隙半导体，而外延生长技术的不成熟引入了许多扩展缺陷，其中一些缺陷对制造器件的电气性能至关重要。因此，人们很期待找出扩展缺陷与器件性能之间的某种深层关系。在这项工作中，基于比较有或没有不同类型扩展缺陷的 4H-SiC 功率二极管的击穿行为，报告了扩展缺陷的几个特征的重要性，包括距离、长度和方向。此外，基于暗场显微镜、近紫外光致发光和形貌的实验结果，以及数值计算的理论分析，揭示了 4H-SiC 器件中沿步进流动方向的特定非对称击穿行为的机制，这源于用于商业 4H-SiC 外延晶片的流行的步进控制外延技术。根据所提出的结果和理解，可以在类似的材料成本下实现更高的生产产量。