SIMILAR POINT-DEFECTS IN CRYSTALLINE AND AMORPHOUS-SILICON

The microscopic nature of defects in ion-implanted crystalline silicon (c-Si) and amorphous silicon (a-Si) has been studied using Mossbauer spectroscopy. The evolution of the local structure around the probe at oms is followed during thermal annealing of ion-beam-created amorphous and ion-beam-damaged crystalline Si. Direct comparison of the Mossbau er parameters of Sb-119 in c-Si and a-Si demonstrates that Sb occupies two distinct sites in each material with similar local environments i n both materials. These sites are identified as fourfold-coordinated s ubstitutional Sb and Sb-vacancy complexes. Annealing of ion-beam-damag ed c-Si at 150-degrees-C causes the Sb-vacancy complex to change from a substitutional Sb adjacent to a vacancy to a more complicated comple x. Annealing of a-Si is shown to reduce distortions in the network, co nsistent with structural relaxation.