Type
Text
Type
Thesis
Advisor
Raghothamachar, Balaji | Dudley, Michael | Venkatesh, T.A..
Date
2016-12-01
Keywords
4H-SiC, Dislocations, Line direction | Engineering -- Materials Science
Department
Department of Materials Science and Engineering
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76069
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
This thesis presents a Synchrotron White Beam X-ray Topography study of dislocations in 4H- SiC single crystals. Basic introduction is given including the crystal structure and atomic arrangement, crystal growth techniques, and the dislocation types. The commonly observed dislocations, including Micropipes (MPs), Basal Plane Dislocations (BPDs), Threading Screw Dislocations (TSDs), Threading Edge Dislocations (TEDs), Threading Mixed Dislocations (TMDs), in 4H-SiC single crystals have been reviewed. Since the extensive application of SiC for power devices is limited by the presence of these dislocations, the minimization, and eventually elimination of these dislocations, have been a major impetus in both research and commercial areas. Therefore, the importance of understanding the formation and multiplication mechanisms of dislocations is highlighted. An effective way to obtain detailed information on dislocations is line direction analysis in combination with Burgers vector determination to enable deducing the origins and glide orientations of various dislocations. To facilitate this, a method which can trace back the directions of the dislocations inside real crystals from two different dislocation X-ray topographic images, is developed and applied. The basic concept combines the crystal structure, rotation parameters and any two line-directions recorded on the X-ray film to determine the actual dislocation line direction in the real crystal. The hexagonal structure of 4H-SiC has been used to develop a computer program using JavaScript to perform this calculation. But the developed program can be easily modified to analyze dislocation line directions in any crystal structure. Application of the program using information from X-ray topographic images quickly produces quantitative results and also provides a graphical visualization of the 3D positions of dislocation lines inside 4H-SiC crystals. Combined with Burgers vector data allows an effective way to analyze the formation mechanism and multiplication tendency of dislocations in crystals. Examples of this implementation are provided to demonstrate the significance of this procedure. | 64 pages
Recommended Citation
Yan, Jianing, "Synchrotron X-ray Topography Analysis of Dislocation Line Directions in 4H-SiC Single Crystals" (2016). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2023.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2023