Direct confirmation of structural differences in single Shockley stacking faults expanding from different origins in 4H-SiC PiN diodes

Abstract

Structural differences are investigated in partial dislocations that have considerably different threshold current densities for single Shockley-type stacking fault (1SSF) expansions in PiN diodes using transmission electron microscopy and scanning transmission electron microscopy as direct observation techniques. It has been found that when the threshold current density is relatively low, a triangular 1SSF, whose oblique and base sides were formed with a pair of Shockley partials, was found. On the other hand, when the threshold current density is relatively high, a similar-shaped triangular 1SSF, whose three sides were almost formed by a single dislocation of one of the Shockley partials, was found. In the latter case, a conversion point from a basal plane dislocation to a threading edge dislocation was also observed around the deepest part of the epilayer. The realistic model for the formation of the triangular 1SSFs has been proposed.