Oxygen-related radiation-induced defects in SiGe alloys

V. P. Markevich, A. R. Peaker, L. I. Murin, N. V. Abrosimov

Research output: Contribution to journalArticlepeer-review

Abstract

Electronic properties of the vacancy-oxygen (V-O) complex and the interstitial oxygen and carbon atom pair (Ci-Oi) in unstrained Si1-xGex crystals (0 < × ≤ 0.06) have been studied by means of capacitance transient techniques. The Si1-xGex crystals were grown by the Czochralski method and were doped with either phosphorus or boron during growth. The V-O and Ci-Oi centres were introduced into the crystals by room temperature irradiation with 4 MeV electrons or with γ-rays from a 60Co source. The enthalpy of electron ionization for the single acceptor level of the V-O centre relative to the conduction band edge, ΔHn, was found to increase with a rate d(ΔHn)/dx = 0.56 eV upon increase in Ge content. The enthalpy of hole ionization for the single donor level of the Ci-Oi centre relative to the valence band edge, ΔHp, was found to decrease with a rate d(ΔHp)/dx = -0.96 eV. For both the V-O- and Ci-Oi-related levels no significant changes in the values of the electron (hole) capture cross section or entropy of ionization with the changes in Ge content were observed. The levels are not pinned to the conduction band edge or to the valence band edge. It is argued that the value of the enthalpy of V-O ionization can be correlated with the lattice parameter or the Si-Si bond length: the larger this parameter, the bigger the enthalpy of the ionization.

Original languageEnglish
Pages (from-to)S2835-S2842
Number of pages7
JournalJournal of Physics Condensed Matter
Volume15
Issue number39
DOIs
Publication statusPublished - 8 Oct 2003

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