A Quantitative Analysis of Electron Energy Loss Spectra of keV Electrons from Thin-Film-Substrate System

Abstract

It is attempted to interpret quantitatively energy losses of keV electrons reflected from targets with a simple phenomenological approach. In the case of a thin layer film on a thick substrate, loss intensities can be represented by a superposition of loss data on both the film and the substrate materials. The results are applied to Si-SiO₂ couples (oxide thickness up to ∼60 Å), which show that the present approach leads to a good agreement between experimentally obtained loss spectra and calculated or synthesized ones. In the calculation, the dependence of inelastic mean free path λ of electron on electron energy E is proposed as λ∝E^0.7±0.1. Also from the curve fitting, it is demonstrated that the loss data give the film thickness within 5% errors.