BACKSCATTERING ANALYSIS OF SI1-YCY LAYERS USING THE C-12(HE-4,HE-4)C-12 RESONANCE AT 4.265 MEV

Resonant backscattering of He-4 ions using the C-12(He-4,He-4)C-12 res onance at 4.265 MeV has been used to analyze C in MBE grown Si1-yCy la yers and in ion implanted Si with C concentrations of the order of one at.%. With ion channeling the ratio of substitutional to interstitial C sites in the Si1-yCy layers was determined and the obtained values for the tetragonal distortion are compared with results from X-ray dif fraction measurements. The measured C amount of an ion implanted sampl e used for calibration was in good agreement with the nominal amount, while the range distribution was about 15% shallower than predicted by TRIM calculations, Strong deviations from the Rutherford scattering c ross section are observed for scattering from Si and the influence due to background from nuclear reactions with Si on the C analysis is dis cussed.