Annealing kinetics of vacancy-related defects in low-dose MeV self-ion-implanted n-type silicon

• Published in: Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2001, Vol.64 (19)
• Main Authors: Pellegrino, P., Leveque, P., Lalita, J., Hallén, Anders, Jagadish, C., Svensson, B. G.
• Format: Article
• Language: English
• Subjects: boron-doped silicon; charge state; crystalline silicon; deep levels; dependence; electron-irradiated silicon; hydrogen-oxygen interaction; level transient spectroscopy; p-type silicon; point-defects
• ISSN: 1550-235X; 1098-0121
• DOI: 10.1103/PhysRevB.64.195211

Silicon samples of n-type have been implanted at room temperature with 5.6-MeV Si-28 ions to a dose of 2 x 10(8) cm(-2) and then annealed at temperatures from 100 to 380 degreesC. Both isothermal and isochronal treatments were performed and the annealing kinetics of the prominent divacancy (V-2) and vacancy-oxygen (VO) centers were studied in detail using deep-level transient spectroscopy. The decrease Of V2 centers exhibits first-order kinetics in both Czochralski-grown (CZ) and float-zone (FZ) samples, and the data provide strong evidence for a process involving migration of V-2 and subsequent annihilation at trapping centers. The migration energy extracted for V-2 is similar to1.3 eV and from the shape of the concentration versus depth profiles, an effective diffusion length less than or equal to0.1 mum is obtained. The VO center displays a more complex annealing behavior where interaction with mobile hydrogen (H) plays a key role through the formation of VOH and VOH2 centers. Another contribution is migration of VO and trapping by interstitial oxygen atoms in the silicon lattice, giving rise to vacancy-dioxygen pairs. An activation energy of similar to 1.8 eV is 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 three reactions, is put forward and shown to yield a close quantitative agreement with the experimental data for both CZ and FZ samples over the whole temperature range studied.