The optical absorption spectra of crystals which had been grown in a H ambient were studied. The specimens were grown, using the float-zone method, in a 1atm H ambient, and the absorption spectra were measured at 6K. Many absorption lines were observed between 1900 and 2200/cm, but they were observed only when the concentrations of C or B were high. This was explained in terms of a so-called A-type swirl, an interstitial-type dislocation loop, which was observed when impurities with smaller covalent radii than that of Si were introduced. It was concluded that the above absorption lines were due to the localized vibrations of H atoms which were bound to interstitial Si atoms.

M.Suezawa: Journal of Applied Physics, 1998, 83[4], 1958-61