REACTION OF DISSOCIATION OF DEFECT COMPLEXES ACCOMPANIED BY THE FORMATION OF A-CENTERS IN SILICON

Calculations are made by the self-consistent X(alpha) discrete variational method, applied in a cluster approximation to stable complexes containing components of a Frenkel pair and an A center. It is shown that there are several mechanisms of the formation and decay of A centers and that they are characterized by different energies. The energy of formation of an A center from a bond-centered complex (silicon-oxygen-silicon atomic chain) is almost twice the energy of formation of an A center by direct knocking out of a host atom and subsequent binding of a vacancy to an oxygen atom. These processes are responsible for the high threshold energy of displacement when this energy is determined from the threshold of appearance of the A centers.