Formation of Si clusters in electron-irradiated SiC studied by electron energy-loss spectroscopy

Electron-irradiation damage in 6H-SiC was examined at room temperature by means of transmission electron microscopy and electron energy-loss spectroscopy (EELS). A detailed analysis of extended energy-loss fine structure (EXELFS) gave unambiguous evidence of the formation of direct Si-Si bonding after prolonged irradiation, where the sample still maintained the well-defined 6H structure, while no appreciable indication of direct C-C bonding was observed. These results suggest that C atoms should be predominantly displaced away compared to Si atoms and the residual Si atoms form small clusters. The changes in the energy-loss near-edge structure (ELNES) were consistent with the appearance of Si clusters. (C) 2001 Elsevier Science B.V. All rights reserved.