Samples of n-type Si were implanted at room temperature with 5.6MeV 28Si ions to a dose of 2 x 108/cm2 and then annealed at temperatures ranging from 100 to 380C. Both isothermal and isochronal treatments were performed and the annealing kinetics of the prominent divacancy (V2) and vacancy-O (VO) centers were studied in detail by using deep-level transient spectroscopy. The decrease in V2 centers exhibited first-order kinetics in both Czochralski-grown and float-zone samples, and the data provide strong evidence for a process involving migration of V2 and subsequent annihilation at trapping centers. The migration energy extracted for V2 was about 1.3eV and from the shape of the concentration versus depth profiles, an effective diffusion length of up to 0.1µm was obtained. The VO center displays a more complex annealing behavior where interaction with mobile H (H) plays a key role through the formation of VOH and VOH2 centers. Another contribution was migration of VO and trapping by interstitial O atoms in the Si lattice, giving rise to vacancy-dioxygen pairs. An activation energy of about 1.8eV was deduced for the migration of VO, in close resemblance with results from previous studies using electron-irradiated samples. A model for the annealing of VO, involving only 3 reactions, was put forward and shown to yield a close quantitative agreement with the experimental data for both Czochralski and float-zone samples over the whole temperature range studied.

Annealing Kinetics of Vacancy-Related Defects in Low-Dose MeV Self-Ion-Implanted n-Type Silicon. P.Pellegrino, P.Lévêque, J.Lalita, A.Hallén, C.Jagadish, B.G.Svensson: Physical Review B, 2001, 64[19], 195211