Deep levels, associated with misfit dislocations in so-called clean and Cu-contaminated p-type Si/Si0.98Ge0.02/Si structures, were considered. In as-grown (non-contaminated) samples, dislocations were found to exhibit a very low recombination activity, detectable with the electron-beam-induced current technique only at low temperatures. Deep-level-transient spectroscopy revealed a dislocation-related hole trap level at Et = Ev + 0.2eV which was identified as band-like. The position of the observed level was close to the theoretically predicted hole trap state of the intrinsic stacking fault between a dissociated dislocation. Contamination with a low Cu concentration (5ppb) gave rise to a large increase of the recombination activity of the dislocations and to the appearance of another dislocation-related defect level at Et = Ev + 0.32eV. Hydrogenation of the Cu contaminated sample by a treatment with an acid solution and subsequent reverse-bias anneal at 380K resulted in the evolution of the levels of substitutional Cu and its complexes with H.

Recombination Activity and Electrical Levels of Clean and Copper Contaminated Dislocations in p-Type Si. O.F.Vyvenko, M.Kittler, W.Seifert, M.V.Trushin: Physica Status Solidi C, 2005, 2[6], 1852-8