X-ray Microbeam Three-Dimensional Topography Imaging and Strain Analysis of Basal-Plane Dislocations and Threading Edge Dislocations in 4H-SiC

This paper demonstrates the X-ray microbeam three-dimensional (3D) topography of basal-plane dislocations (BPDs) and threading edge dislocations (TEDs) in 4H-SiC. Stereographic images showing the propagation of BPDs from a substrate to an epilayer and the conversion of BPDs into TEDs near the epilayer/substrate interface are successfully obtained. The narrowing of BPD images is observed just before the BPD-TED conversion points. The images of effective misorientations Δω provide a spatial resolution of 1–2 µm for a TED, and the range of Δω corresponds to strains on the order of ±10-5. We also discuss the image-formation mechanism in 3D topography.