DETAILS OF THE DAMAGE PROFILE IN SELF-ION-IMPLANTED SILICON

Raman spectra excited at two laser wavelengths are used to study the d amage in self-implanted silicon. Depending on the implantation conditi ons, a three-layer structure can be constructed: a damaged surface cry stalline layer (dsc-Si), an amorphous layer (a-Si) and a damaged inter ior crystalline layer (dic-Si). Raman spectra can provide the structur al details of these layers, together with the Rutherford backscatterin g-chanelling technique. Examination of the scattering intensities show s that the contribution to the Raman signals from different layers can be distinguished and separated. Further analysis of the Raman data re veals a defect-activated low-frequency band in the dsc-Si layer which is sensitive to the damage and may be used for the characterization of dsc-Si. For totally amorphized samples the two Raman spectra excited at 457.9 and 647.1 nm show different scattering intensity ratios for t he optical- and acoustic-like phonons. This novel result may indicate a depth-dependent variation of the disordering in the amorphous layer. Quantitative comparison between the calculated and measured Raman sca ttering intensities provides the scattering efficiency ratios of dsc-S i and a-Si in samples comprising both dsc- and a-Si layers.