The depth distributions of O-related defects in separation-by-implanted O wafers were determined from measurements of Doppler broadening spectra of the annihilation radiation. Vacancy–O complexes were introduced by implanting 180keV O into Si substrates to between 2 x 1017 and 6 x 1017/cm2. Their sizes decreased below the sub-surface region (less than 100nm) because an agglomeration of vacancy-type defects was suppressed by the interaction between vacancies and O atoms. As the dosage was increased, in the region near the projected range of O, atomic rearrangement of vacancy-type defects occurred, and this rearrangement was considered to introduce SiOx (x < 2) that was stable at high annealing temperatures. Oxygen-related defects were presented in the superficial Si layer even after annealing at 1350C. The concentration of such defects was low when the substrate was implanted with a dose of 4 x 1017/cm2.

Oxygen-Related Defects in Low-Dose Separation-by-Implanted Oxygen Wafers Probed by Monoenergetic Positron Beams. A.Uedono, Z.Q.Chen, A.Ogura, H.Ono, R.Suzuki, T.Ohdaira, T.Mikado: Journal of Applied Physics, 2001, 90[12], 6026-31