A novel procedure for elimination of the peak deviations in LEIS spectra influenced by the primary ion beam profile

Quantitative surface composition analysis using low energy ion scattering (LEIS) can be obstructed by the deviations introduced by the primary beam profile and the analyzer optics. A novel procedure is presented for excluding these deviations in LEIS measurements. The LEIS spectra were calculated from the assumed energy distribution, primary beam profile and the analyzer optics. From the calculated energy spectra, the instrumental functions were determined as a deconvolution of the energy spectra and corresponding energy distributions. The obtained instrumental functions can be very well approximated by the Gaussian. It is convincingly shown that the energy distribution evaluation, by means of the deconvolution of the energy spectrum and the calculated instrumental function, significantly suppresses the problems of qualitative (the peak shift) and the quantitative (the peak intensity deviation) surface composition analysis due to the different geometric profiles of the primary ion beam. The calculation method was then successfully applied for the analysis or the real experimental data that are not too noisy.