The recombination-enhanced migration of interstitial Fe in the vicinity of substitutional B was investigated by using space charge techniques, combined with minority carrier injection at temperatures below 200K. The temperature dependence of the creation rates of metastable pairs revealed a small negative activation energy. This implied that the recombination-enhanced defect reaction for each defect was athermal and that the recombination energy was large relative to the thermal energy which was required in order to surmount the reaction barrier. Four electron traps and a hole trap were observed as structurally metastable Fei-Bs pairs after injection. The creation and annihilation of these pairs by injection was analyzed in terms of the theory of recombination-enhanced defect reactions. The migration rates for traps, E2, E5 and H2, were much lower than those for E3, E4, and H2*. The attribution of the E2, E5 and H2 traps to Td sites could explain the migration behavior quite well; in addition to the thermal and electrical properties. The traps, E3, E4, and H2, seemed to be attributable to unstable sites such as hexagonal sites, or to lattice strain-related sites in the vicinity of Bs.

H.Nakashima, T.Sadoh, T.Tsurushima: Materials Science Forum, 1995, 196-201, 1351-6