In order to study both the generation rates and mobilities of point defects due to electron irradiation, the optical-absorption spectra of complexes of H and point defects generated by the low-temperature electron irradiation of hydrogenated Si crystals were measured and analyzed. Specimens were doped with H by heating in H2 gas at 1300C followed by quenching. They were then irradiated with 6MeV electrons at 270, 200, 130 and 77K. Their optical absorption spectra at 7K were measured using a Fourier transform infra-red spectrometer. Many optical absorption peaks were observed which were due to localized vibrational modes of H bound to various point defects. The irradiation temperature dependence of concentrations of some H-point defect complexes was not monotonic contrary to the prediction of metastable Frenkel pair models. Relative intensities of those

peaks depended upon the irradiation temperature and were interpreted to be due to the relative mobilities of various point defects. The migration energies of a self-interstitial and a Frenkel pair relative to that of a vacancy were determined.

Migration energies of Point Defects during Electron Irradiation of Hydrogenated Si Crystals. M.Suezawa, Y.Takada, T.Tamano, R.Taniguchi, F.Hori, R.Oshima: Physical Review B, 2002, 66[15], 155201 (6pp)