A study was made of the dependence of the H2* concentration upon the electron-irradiation dose to which hydrogenated crystals were subjected. The specimens were prepared from high-purity, B-doped or C-doped crystals. They were doped with H by annealing in H2 gas at 1300C and quenching. They were irradiated with 3MV electrons at room temperature. Optical absorption spectra were measured at 7K by means of Fourier-transform infra-red absorption spectroscopy. The intensity of the 1838/cm peak, which was due to H2, was weakest in C-doped material, intermediate in B-doped material and strongest in high-purity material. This tendency was related to the intensity of the 2122/cm peak; which was due to a complex involving a vacancy and two H atoms. The intensity of the 1838/cm peak depended linearly upon the electron dose at low doses. The results suggested 2 mechanisms for the formation of H2*; from H2. That is, a vacancy plus H2 or a Frenkel pair plus H2.

The Formation of H2* by Electron-Irradiation of Hydrogenated Si M.Suezawa: Japanese Journal of Applied Physics - 2, 1999, 38[7A], L758-60