Improved ARXPS data interpretation using near-surface measuring angles

The increasing number of applications of very thin films requires both reliable thin-layer and interface characterization. A powerful nondestructive method for depth-profile characterization in the nanometer thickness range is the angle-resolved X-ray photoelectron spectroscopy (ARXPS). One limitation of ARXPS is that, in the past, its use has been restricted away from near-surface angles because of the increasing effects of elastic electron scattering in this angular region. In this article, we present an ARXPS data interpretation method that accounts for elastic scattering effects, thus allowing the use of the whole angular region. Its concept is based on two main parts: (i) the Monte Carlo computer simulation of reliable ARXPS data for complex near-surface structures considering elastic scattering and (ii) the interpretation of these data using a standard analysis procedure extended by an empiric angle correction. Besides the general potential of this procedure, we also discuss its dependence on parameters such as material, overlayer thickness, or angle selection. As an impressive application, the unique identification of layer sequences for thin overlayers less than 1 nm is presented. Thus, the method is readily applicable in the field of interface formation studies. Copyright (c) 2012 John Wiley & Sons, Ltd.