Single-crystal specimens of 4H SiC were subjected to electron irradiation. A wide range of doses and dose rates was used. In addition, a more limited investigation of localized hydrogen and helium implantation of 4H SiC was carried out. The electron energies were sufficient to cause atomic displacements; thus creating vacancies and self-interstitials in the irradiated samples. Following electron-irradiation or implantation, the samples were studied using low-temperature (~7K) photoluminescence microscopy. It was found that some of the defect centres migrated over large distances outside of the irradiated regions, and that this distance increased with increasing dose. One possible explanations for this was based upon the absorption, by the defects, of light created by the recombination of electrons and holes in the irradiated or implanted region. The other involved the consequences of recombination-enhanced migration.

Long-Range Migration of Intrinsic Defects during Irradiation or Implantation. J.W.Steeds, W.Sullivan, A.Wotherspoon, J.M.Hayes: Journal of Physics - Condensed Matter, 2009, 21[36], 364219