Vacancy-type defects in separation-by-implanted O wafers were probed using mono-energetic positron beams. The Doppler broadening spectra of annihilation radiation and the lifetime spectra of positrons were measured. The species of the defects in Si-on-insulator layers were identified as O clusters or small O precipitates, and the positrons were considered to be trapped by open spaces adjacent to such defects. The mean size of the open spaces was estimated to be larger than that of a hexavacancy. After annealing in a H atmosphere at 600C, both the lifetime of positrons trapped by the defects and the annihilation probability of positrons with high-momentum electrons decreased. These facts were attributed to the trapping of H atoms by the open spaces.

Defects in Silicon-on-Insulator Wafers and their Hydrogen Interaction Studied by Monoenergetic Positron Beams. A.Uedono, Z.Q.Chen, A.Ogura, R.Suzuki, T.Ohdaira, T.Mikado: Journal of Applied Physics, 2002, 91[10], 6488-92