Dresden 2017 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 21: Thin Film Characterisation: Structure Analysis and Composition II

DS 21.11: Vortrag

Dienstag, 21. März 2017, 12:15–12:30, CHE 91

Improved XPS Background Fitting with a Modified Tougaard Universal Cross Section Using the Example of Aluminium — •Manuel Monecke, Georgeta Salvan, and Dietrich R.T. Zahn — Semiconductor Physics, Technische Universität Chemnitz, D-09107 Chemnitz, Germany

X-ray photoelectron spectroscopy (XPS) spectra are commonly fitted in a narrow binding energy regime of several eV using either a Shirley [1] or a Tougaard [2] background. We present an improved approach for XPS background fitting using reflective electron energy loss spectroscopy (REELS) data to calculate the inelastic electron scattering cross section (IESCS). As example the photoemission spectrum of aluminium was calculated in the binding energy range from 50 to 240 eV (Al 2s and 2p). We first fit the REELS spectrum considering the contribution of elastic scattered, directly excited surface plasmon, and inelastically scattered electrons. The results of this fit are then taken as starting parameters to fit the XPS spectrum. The fit results show a much better agreement with the measured spectrum as compared to those obtained with the conventional Tougaard background. Just as important, this method reveals the presence of several satellite peaks in the region of the plasmon peaks becoming apparent due to the simultaneous fitting of the detailed IESCS for the background calculation and XPS peak functions. This sensitivity to hidden satellite peaks can become a powerful tool to gain more knowledge from XPS spectra. [1] D. Shirley, Phys. Rev. B, Vol. 5, Nr. 12 [2] S. Tougaard, Solid State Commun., Vol. 69, Nr. 9