X-ray microbeam three-dimensional topography for dislocation strain-field analysis of 4H-SiC

摘要

This paper describes the strain-field analysis of threading edge dislocations (TEDs) and basal-plane dislocations (BPDs) in 4H-SiC using x-ray microbeam three-dimensional (3D) topography. This 3D topography enables quantitative strain-field analysis, which measures images of effective misorientations (Δω maps) around the dislocations. A deformation-matrix-based simulation algorithm is developed to theoretically evaluate the Aco mapping. Systematic linear calculations can provide simulated Δω maps (Δω_(sim) maps) of dislocations with different Burgers vectors, directions, and reflection vectors for the desired cross-sections. For TEDs and BPDs, Δω maps are compared with Δω_(sim) maps, and their excellent correlation is demonstrated. Two types of asymmetric reflections, high- and low-angle incidence types, are compared. Strain analyses are also conducted to investigate BPD-TED conversion near an epilayer/substrate interface in 4H-SiC.