Spectroscopic ellipsometry and x-ray photoelectron spectroscopy studies of the annealing behavior of amorphous Si produced by Si ion implantation

The dielectric functions of a-Si prepared by Si ion implantation in Si and of subsequently thermally annealed a-Si have been measured by means of spectroscopic ellipsometry. Differences are observed that may be accounted for only partially by differences in density, recrystallization during preparation of the anneal-stabilized a-Si state, or differences in the surface condition of the samples. Intrinsic changes in the bond polarizability are thus indicated. Comparison of the x-ray photoemission results for the Si 2p core levels and the valence band states of the as-implanted and anneal-stabilized a-Si samples reveals measurable changes in the valence charge distribution sufficient to substantiate a change in the bond polarizability.