Present limits to the calculation of auger line intensities for film-substrate systems

Abstract

A new and simple algebraic expression for calculation of backscattering factors in the film-substrate systems has recently been proposed. The limits of its use with the Gryzinski ionization cross-section to calculate Auger line intensities were, however, not thoroughly discussed. We have examined more closely its range of validity using Monte Carlo simulation and recent experimental data available. Film-substrate systems of carbon films on Cu, Sn and Ta substrates and Cu films on C, Sn and Ta substrates were investigated. Our results have indeed shown that there are disagreements. Contributing factors to some of the disagreements include the proposed backscattering factor expression and the ionization cross-section used. New proposals for quantification were suggested using an alternative interpolation factor taking into account substrate scattering behavior and the Bethe ionization cross-section. Results of the new proposals did show significant improvements with the use of the Bethe ionization cross-section for the case of carbon film-substrate systems. Results for Cu film-substrates were not conclusive, with only one evident improvement for Cu/C using the Bethe cross-section.