Analysis of contrasts and identifications of Burgers vectors for basal-plane dislocations and threading edge dislocations in 4H-SiC crystals observed by monochromatic synchrotron X-ray topography in grazing-incidence Bragg-case geometry

• Published in: Philosophical magazine (Abingdon, England) England), 2012-12, Vol.92 (36), p.4599-4617
• Main Authors: Matsuhata, Hirofumi, Yamaguchi, Hirotaka, Ohno, Toshiyuki
• Format: Article
• Language: English
• Subjects: Burgers vector; Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; Deformation and plasticity (including yield, ductility, and superplasticity); dislocations; Exact sciences and technology; grazing-incidence; Linear defects: dislocations, disclinations; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Physics; SiC; Structure of solids and liquids; crystallography; X-ray topography
• ISSN: 1478-6435; 1478-6443
• DOI: 10.1080/14786435.2012.716168

Contrasts of dislocations in the sub-surface region of the Si-face of a 4H-SiC wafer were observed by monochromatic synchrotron X-ray topography in grazing-incidence Bragg-case geometry. Basal-plane dislocations show very characteristic contrast depending on their Burgers vectors, running directions, and types of dislocations, whether they are screw dislocations, C-core edge dislocations, or Si-core edge dislocations. The rules for contrasts of basal-plane dislocations are summarized. It is shown that by observing those contrasts at fixed diffraction conditions, Burgers vectors of the basal-plane dislocation can be identified without performing a g · b analysis in some cases. Threading edge dislocations also have very characteristic contrasts depending on the angles between the projected g and their Burgers vectors. It is shown that Burgers vectors of threading edge dislocations can be determined uniquely by observing their characteristic contrasts without performing g · b analysis. Contrast mechanisms for these dislocations in grazing-incidence X-ray topography are discussed.