Investigation on dislocation and deflection morphology of PVT-grown on-axis 4H-SiC crystals

Abstract The morphologies of dislocation etch pits and dislocation deflections of on-axis 4H-SiC substrate etched by molten KOH were observed with the help of a microscope. Based on experimental observation and etch mechanism, a method for the identification of threading edge dislocations, threading screw dislocations (TSDs) and threading mixed dislocations was proposed. The details about the inner micro-structure of threading edge dislocations and TSDs were observed by laser scanning confocal microscope and scanning electron microscopy. The morphologies and the cross-sectional views of the basal plane dislocation formed by threading edge dislocation were observed and two models were formed to explain it.