Characterization of Threading Edge Dislocation in 4H-SiC by X-ray Topography and Transmission Electron Microscopy

摘要

A threading dislocation (TD) in 4H-SiC, which was currently interpreted as a perfect threading edge dislocation (TED) by synchrotron monochromatic-beam X-ray topography (SMBXT) and molten KOH etching with Na_2O_2 additive, was investigated using weak-beam dark-field (WBDF) and large-angle convergent-beam electron diffraction (LACBED) methods. The TD was suggested to be dissociated into a dislocation pair which can be observed in the WBDF image of g= 1210. The TD, which was identified as b//[1210] by SMBXT observation, was unambiguously determined as b=l/3[1210] by LACBED analysis. In the case of perfect TED, it was found that the direction of Burgers vector derived from SMBXT observation corresponds to LACBED analysis.