Improved calculation of the backscattering factor for quantitative analysis by Auger electron spectroscopy

Abstract

Based on a Monte Carlo simulation method, an improved calculation of the backscattering factor in quantitative analysis by Auger electron spectroscopy has been performed by integrating several aspects of recent progresses in the related fields. The calculation used a general definition of backscattering factor, more accurate ionization cross section, up-to-date Monte Carlo model of electron inelastic scattering, and a large number of electron trajectories to ensure less statistical error. The results reveal several noticeable properties of backscattering factor, i.e., its slow variation with primary energy at higher overvoltage ratios, and dependence on the geometrical configuration of a detector. However, only for large emission angles of Auger signals a considerable angular dependence of backscattering factor is found. Specifically a calculation is carried out for detection in the solid angles of a cylindrical mirror analyzer. This backscattering factor can be less than unity for very low primary energies closing to ionization energy and/or for large incident angles. The physical cause has been detailed and analyzed.