Threading dislocation classification for 4H-SiC substrates using the KOH etching method

Abstract

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.