Interstitial defect reactions in silicon

A five level hierarchy of interstitial defect reactions has been observed in silicon involving oxygen, carbon, Group III and Group V impurities. The deep electronic states of the mobile interstitial defects provide a proximity charging effect near a reactant which yields a Fermi level dependent reaction cross section. Local structural transformations are observed which exhibit a threshold charge state behavior. The equilibrium structure of the metastable interstitial iron-acceptor pairs is determined by long range electrostatic, short range elastic and covalency energy terms. Each structural alternative, though compositionally identical, is properly treated as a separate thermodynamic entity. (author) 34 refs., 7 figs., 3 tabs