Vacancy-type defects in plasma immersion B-implanted Si were studied by using a mono-energetic positron beam. The Doppler broadening spectra of the annihilation radiation were compared with the spectra predicted using the projector augmented-wave method. In the case of the as-doped sample, the vacancy-rich region was found to be localized at a depth of 0 to 10nm, and the main defect types were divacancy–B complexes. After spike rapid thermal annealing at 1075C, the line-shape parameter of the Doppler broadening spectra corresponding to the high B-concentration region (4 to 30nm) was smaller than the characteristic line-shape parameter value obtained for defect-free Si. Using a detailed analysis of the Doppler broadening spectra, the decrease in the line-shape parameter value was attributed to the trapping of positrons by negatively charged B clusters such as icosahedral B12.

Vacancy-Boron Complexes in Plasma Immersion Ion-Implanted Si Probed by a Monoenergetic Positron Beam. A.Uedono, K.Tsutsui, S.Ishibashi, H.Watanabe, S.Kubota, Y.Nakagawa, B.Mizuno, T.Hattori, H.Iwai: Japanese Journal of Applied Physics, 2010, 49[5], 051301