Dislocation contrast on X‐ray topographs under weak diffraction conditions. Issue 4 (30th July 2021)

• Record Type: Journal Article
• Authors: Peng, Hongyu; Ailihumaer, Tuerxun; Liu, Yafei; Raghotharmachar, Balaji; Huang, Xianrong; Assoufid, Lahsen; Dudley, Michael
• Is Part Of: Journal of applied crystallography. Volume 54:Issue 4(2021)
• Page Start: 1225
• Page End: 1233
• Publication Date: 2021-07-30
• Subjects: X‐ray topography -- weak diffraction -- dislocations -- ray‐tracing simulation; Crystallography -- Periodicals; 548.05
• DOI: 10.1107/S1600576721006592
• Languages: English
• ISSNs: 0021-8898

Abstract

Abstract : The contrast of dislocations in 4H‐SiC crystals shows distinctive features on grazing‐incidence X‐ray topographs for diffraction at different positions on the operative rocking curve. A misorientation model together with a ray‐tracing simulation effectively interpret the features on X‐ray topographs under weak diffraction conditions. Abstract : The contrast of dislocations in 4H‐SiC crystals shows distinctive features on grazing‐incidence X‐ray topographs for diffraction at different positions on the operative rocking curve. Ray‐tracing simulations have previously been successfully applied to describe the dislocation contrast at the peak of a rocking curve.The present work shows that the dislocation images observed under weak diffraction conditions can also be simulated using the ray‐tracing method. These simulations indicate that the contrast of the dislocations is dominated by orientation contrast. Analysis of the effective misorientation reveals that the dislocation contrast in weak‐beam topography is more sensitive to the local lattice distortion, consequently enabling information to be obtained on the dislocation sense which cannot be obtained from the peak.