The thermal evolution of multioxygen–vacancy (VOn) centres produced in electron-irradiated Czochralski-grown Ge-doped Si was studied by means of infra-red spectroscopy. Two groups of samples with low [Ge] ≤ 1017/cm3 and high [Ge] = 2 x 1020/cm3 were used. It was found that the annealing temperature of vacancy–O complexes (A-centres) produced in the course of irradiation at room temperature was substantially decreased in the samples with high [Ge]. This effect was explained taking into account an influence of the elastic stresses due to Ge atoms in the Si lattice on the migration barrier of A-centres as well as the rate of O-related reactions, i.e. VO+Oi→VO2, VO+SiI→Oi, etc. It was also found that the ratio of A-centres converted to VO2 defects was smaller in the material with high [Ge]. The same was also true for the conversion reaction VO2+Oi→VO3. Contrary, the next reaction VO3+Oi→VO4 exhibited a markedly enhanced rate if the Ge content was high. This observation could be explained considering the effects of Ge-induced stresses in the Si lattice on the successive trapping of O atoms by A-centres and other VOn complexes as well as on the enhanced diffusivity of O.

IR Studies of Oxygen–Vacancy Defects in Electron-Irradiated Ge-Doped Si. C.A.Londos, A.Andrianakis, D.Aliprantis, H. Ohyama, V.V.Emtsev, G.A.Oganesyan: Physica B, 2007, 401-402, 487-90