Observation of low angle grain boundaries and micropipes in 6H-SiC single crystal by synchrotron radiation black reflection white-beam topography

Low angle grain boundaries and micropipes in 6H-SiC wafer were observed by synchrotron radiation back refection white-beam topography.Low angle grain boundaries are polygonized into 〈11- 00〉 directions.Based on the strain field around the screw dislocation and the diffraction geometry,we simulated the topograph of unit c screw dislocation.The calculated values were in good agreement with the experimental observation.The micropipes with different Burgers vectors in topograph were distinguished by this method.