An examination of double positioning boundaries and interface misfit in beta-SiC films on alpha-SiC substrates

Beta-SiC thin films epitaxially grown on 6H-SiC (0001) substrates were examined via scanning-reflection x-ray topography (XRT) and x-ray rocking curve analysis. The lattice misfit between the (111) plane of the β-SiC epitaxial layer and the (0001) plane of the 6H-SiC substrate was determined to be 7.6×10-4. Boundaries separating regions of the β-SiC film rotated from each other by 60°were observed and identified by XRT as double positioning boundaries (DPBs), which are a special type of twin boundary. The XRT maps showed that the mosaic structure examined via optical microscopy was also caused by the DPBs. Finally, many stacking faults were generated at the boundaries as revealed by plan-view transmission electron microscopy, indicating the high internal energy of these DPBs. The formation mechanisms of the DPBs is also discussed.

Duke Scholars

Author Jeffrey Glass Electrical and Computer Engineering