Dislocation Characterization in 4H-SiC Crystals

Definitive correlations are presented between specific types of dislocations identified via Synchrotron White Beam X-Ray Topography (SWBXRT) and identified via selective etching of 4H-SiC substrates. A variety of etch conditions and the results on different faces of SiC substrates and epiwafers are examined. Hillocks formed on the carbon face of the substrate after KOH etching correlate very well to TSDs identified via SWBXRT. Topography of substrates and of vertical crystal slices reveals a large proportion of Threading Mixed character Dislocations (TMDs) in the population of Threading Screw Dislocations.