Vacancy-related defects that were introduced into n-type material during annealing or Al diffusion at 1000 to 1250C were studied. Various ambients (Ar, N, Cl) were used to create a vacancy supersaturation during heat treatment. Three deep-level centers were identified whose formation was governed by the presence of vacancies. An asymmetrical diffuse X-ray scattering was observed near to the surface of a crystal that had been irradiated with thermal neutrons and annealed in a Cl-containing atmosphere. This scattering was attributed to the formation of structural defects of vacancy type. In the same region of the crystal, the concentration of the E7 center was an order of magnitude higher than that of other deep-level centers. It was suggested that the formation of this center occurred under conditions of vacancy supersaturation.

N.A.Sobolev, E.I.Shek, A.I.Kurbakov, E.E.Rubinova, A.E.Sokolov: Applied Physics A, 1996, 62[3], 259-62