In hydrogenated high-purity Si, the vacancy-oxygen (VO) center was shown to anneal already at temperatures below 200C and was replaced by a center, identified as a vacancy-oxygen-hydrogen complex, with an energy level 0.37eV below the conduction-band edge and a rather low thermal stability. At long annealing times, the process was reversed and the concentration of the latter defect was reduced, while the VO center partly recovers. The divacancy (V2) center anneals in parallel with the initial annealing of the VO center, and the loss in V2 exhibits a one-to-one proportionality with the appearance of a hole trap 0.23eV above the valence-band edge attributed to a divacancy-hydrogen (V2H) center.

Rapid Annealing of the Vacancy-Oxygen Center and the Divacancy Center by Diffusing Hydrogen in Silicon. J.H.Bleka, I.Pintilie, E.V.Monakhov, B.S.Avset, B.G.Svensson: Physical Review B, 2008, 77[7], 073206 (4pp)