Identification of the Basal Plane Component of the Burgers Vector of Small Dislocations in 6H SiC Using Birefringence Microscopy

Abstract

Using 6H SiC wafers including regions with a varying residual stress, the birefringence pattern of almost vertical dislocations is measured and modeled. We show that it is possible to identify the basal plane component of "small" dislocations by a quantitative fit of the birefringence pattern. Combining birefringence and etch pit detection after KOH etching shows that most of the vertical dislocations are of a mixed nature, exhibiting both an edge and a screw component.