Nondestructive quantitative XPS imaging of depth distribution of atoms on the nanoscale

Abstract

It is well known that XPS imaging based on the peak intensity gives limited quantitative information. Recently, we found Tougaard's algorithm [J. Vac. Sci. Technol. 2003; A21: 1081] very robust for automatic data processing and we made a qualitative test of its ability to give an image of the amount of substance (AOS) in the outermost few nanometers as well as images of surface and bulk localized atoms [Surf. Sci. 2006; 600: 3015]. In this work, we perform a quantitative test of the algorithm's ability to produce images of Ag taken from a series of samples with increasing thicknesses of plasma patterned octadiene (2, 4, 6 and 8 nm) on Ag substrates. The obtained images of the amount of silver atoms in the outermost few nanometers of the samples were in good agreement with the nominal thicknesses. For a given sample, different sectioning of depth distributions of atoms were made, which clearly prove the ability of the method for quantitative and nondestructive determination of in-depth distribution of atoms. We have shown that the algorithm is suitable to make 3D image of the nanoscale. Copyright © 2008 John Wiley & Sons, Ltd.