Calculation of backscattering correction factors in AES for compounds: Unraveling matrix effects

Backscattering correction factor (BCF) data are essential for quantitative Auger electron spectroscopy (AES) analysis. This study computes BCFs for nine oxides and three zinc chalcogenides by using a Monte Carlo method that incorporates dielectric function theory for discrete inelastic events and Mott scattering cross section for elastic interactions. Results demonstrate that the BCF is highly sensitive to the mean atomic number of the matrix. Comparative analysis with NIST data reveals that the continuous slowing down approximation (CSDA) based model systematically underestimates the BCFs for heavy metal oxides, such as HfO2 and ZrO2. In these high-Z matrices, intense large-angle elastic scattering spatially distributes electron trajectories to be close to the surface region and thereby substantially increasing BCF. While our calculations align perfectly with NIST values for low-Z chalcogenides, the pronounced discrepancies in the heavy oxides definitively delineate the physical limits of the CSDA approach. Ultimately, this work provides a refined theoretical basis for eliminating systematic uncertainties in high-precision quantitative surface analysis by AES.