Abstract 4H–SiC and 6H–SiC epitaxial layers have been characterized by the scanning internal photoemission microscopy (SIPM) method based on use of Ni Schottky contacts. Geometrical patterns with widths of a few tens of microns were observed in the photoyield (Y) maps obtained for the 4H–SiC samples with a slightly lower Schottky barrier and a larger ideality factor than those in the current-voltage (I–V) characteristics; these patterns are caused by stacking faults located in the depletion region. SIPM also provided clear images of small particles adhered to the sample, which appeared as dark spots in the Y maps. These particles behaved as insulating materials and blocked the photocurrent flow; this behavior could not be detected from the conventional I–V characteristics. On the 6H–SiC samples, the violet SIPM measurements revealed surface pits, which originated from screw dislocations and were also shown as dark spots. We consider SIPM to be a powerful tool for investigation in inhomogeneities in crystal quality in conjunction with the electrical characteristics.

中文翻译：

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使用内部光电显微技术绘制 SiC 肖特基触点中的大结构缺陷

摘要 4H-SiC 和 6H-SiC 外延层已通过基于 Ni 肖特基接触的扫描内部光电显微镜 (SIPM) 方法进行表征。在为 4H-SiC 样品获得的光产率 (Y) 图中观察到宽度为几十微米的几何图案，其肖特基势垒略低，理想因子比电流-电压 (I-V) 特性中的略低; 这些模式是由位于耗尽区的堆垛层错引起的。SIPM 还提供粘附在样品上的小颗粒的清晰图像，在 Y 图中显示为暗点。这些颗粒充当绝缘材料并阻止光电流流动；这种行为无法从传统的 I-V 特性中检测到。在 6H-SiC 样品上，紫色 SIPM 测量显示表面凹坑，它起源于螺位错，也显示为黑点。我们认为 SIPM 是结合电特性研究晶体质量不均匀性的有力工具。