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The active approach for background modeling is described in this report. Under this technique, the background is assessed during the optimization of the peak parameters. In contrast, under the traditional (static) approach, the background is defined prior to peak fitting. The active has many advantages over the static, such as that the peak areas are often underestimated under the static approach. The active technique allows for treating the background as a combination of various background types. There are many reports in the literature where some of the features of the active approach are employed. Also described in this report is the Shirley–Vegh–Salvi–Castle (SVSC) background, which is a variant of the Shirley–Proctor–Sherwood method that does not require iterations. The advantages of the SVSC over the Shirley–Proctor–Sherwood background are fully described. Copyright © 2014 John Wiley & Sons, Ltd.

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The background in X-ray photoelectron spectroscopy data originates, partially, from inelastically scattered photoelectrons. In fact, the current theoretical methods for calculating the background intensity are based on electron energy losses. However, a critical part of the experimental signal, which is known as the Shirley background, cannot be described within the current formalisms. This suggests that the Shirley electrons are not associated with energy losses of photoelectrons and must originate from a different photoexcitation phenomenon with a cross section of its own.We propose a mechanism based on core channeling as the physical origin of the Shirley signal.

The structure of TiN/HfO2 nanofilms grown on InxGa1−xAs substrates was assessed through angular-resolved x-ray photoelectron spectroscopy. The quantitative analysis made possible determining the thickness and composition of the various layers constituting the nanofilms treated at different temperatures (un-annealed, 500  °C/120 s and 700  °C/10 s). The TiN layer is crucial to prevent oxygen desorption from the dielectric during annealing. Small amounts of oxidized gallium and metallic arsenic are located at the HfO2/InGaAs interface. The thickness of the HfO2 layer remains stable under the thermal treatments. Annealing affects the In 3d5/2 and Ga 3p signals. From the angular dependence of the peak intensities and the detailed knowledge of the structure of the films, it was possible to determine that annealing causes In and Ga out-diffusion into the metallic layer, and also to quantify the amount of transported matter. This, along with density functional theory calculations, allowed for an estimation of the activation energy of the diffusion of indium through HfO2.