3D structure of threading screw dislocation at a deep location in 4H-SiC using 3D micro-X-ray topography

We used 3D micro-X-ray topography (3D mu-XRT) to construct a 3D structure of the threading screw dislocations (TSDs) in 4H-SiC. The 00012 diffraction condition, which can observe the strain field at a deep location in the sample, was employed in the 3D mu-XRT geometry. The dislocation core-lines of TSDs propagating from the surface to the interior of the sample were successfully captured spatially, and TSDs parallel to and inclined from the 0001 axis were both confirmed. Either the component 1 over bar 1 over bar 20 or 1 over bar 100 of the Burgers vector is considered to be mixed in the inclined TSD. To verify this suggestion, scanning electron microscopy (SEM) and cathodoluminescence (CL) spectroscopy were performed on the molten-alkali-etched TSDs. Both the SEM shapes and CL intensities of the TSD etch pits with inclination showed the features of the mixed component, supporting the correlation between the inclination and mixed component in TSD.