Monte Carlo simulation of Auger electron emission from thin film on substrate

A Monte Carlo simulation of production and emission of Auger electron signals in Auger electron spectroscopy (AES) has been performed to calculate the dependence of Auger electron intensity on film thickness for a film/substrate specimen. The electron spectrum is simulated, covering the energy range from the elastic peak down to Auger electron peak, by including bulk loss peak of electronic excitation. This simulation is based on the use of Mott's cross section for electron elastic scattering and Penn's dielectric function approach to electron inelastic scattering. Bulk plasmon excitation peaks contributed from both film and substrate are found in the low loss region near the elastic peak and the AES signal peak. The background subtraction was then performed for the simulated Auger electron spectrum, leading to obtain the approximate exponential decay behavior of Auger signal intensity varied with the film thickness. It is found that single value of effective attenuation length (EAL) is not enough for an accurate measurement of film thickness. We define two attenuation parameters to characterize the decay functional shape used as the calibration curve for accurate film thickness determination if the universal expression on experimental condition will be found. (C) 2017 Elsevier B.V. All rights reserved.