We have studied the threading dislocations of 4H-SiC substrates with different conductivity types by means of molten KOH defect selective etching. The etch pit sectional view and morphology evolution of the threading dislocations with etching time were observed with the help of a LEXT OLS4000 3D laser confocal microscope. Combining experimental observation with theoretical analysis of the corrosion process and dislocation energy field characteristics, a method for identification of threading screw dislocations and threading edge dislocations was proposed based on etch pit sectional view information and etch pit angle. An investigation of the defect corrosion process can promote a deep understanding of the chemical etching mechanism of SiC single crystals.

中文翻译：

---

使用KOH蚀刻方法对4H-SiC衬底进行螺纹位错分类

我们已经通过熔融KOH缺陷选择性刻蚀研究了具有不同导电类型的4H-SiC衬底的螺纹位错。在LEXT OLS4000 3D激光共聚焦显微镜的帮助下，观察了蚀刻坑的截面图和随时间变化的螺纹位错的形貌演变。结合实验观察和腐蚀过程及位错能场特性的理论分析，提出了一种基于刻蚀坑断面图信息和刻蚀坑角的识别螺丝钉位错和螺纹边缘位错的方法。对缺陷腐蚀过程的研究可以促进对SiC单晶化学腐蚀机理的深入理解。