In this study, a low-cost technique, energy dispersive spectroscopy (EDS), was used to explore the application of X-ray microanalysis in depth determination of metallic films. Al, Ni and Au films with varied thicknesses from 50 to 400 nm were deposited on silicon (Si) substrates by magnetron sputtering. Electron beam energies ranging from 4 to 30 keV were applied while other parameters were kept constant to determine the electron beam energy required to penetrate the films. The effect of the atomic number of the metallic films on the penetration capability of the electron beam was investigated. Based on the experimental results, mathematical models for Al, Ni and Au films were established and the interaction volume was simulated using a Monte Carlo program. The simulations are in good agreement with the experimental results. Al/Ni/Au multilayers were also studied. (c) 2005 Elsevier B.V. All rights reserved.