Reproducibility of XPS analysis for film thickness of SiO2/Si by active Shirley method

The active Shirley method has been recently proposed for reproducibly estimating the background and peaks of X-ray photoelectron spectroscopy (XPS) spectra because of its automatic tuning of starting and ending points of the Shirley-type background spectra. This reproducibility is significantly affected not only by a software algorithm of the active Shirley method but also by a choice of the initial ending points or a shape of Voigt function. In this work, we provided an example of the reproducibility of XPS analysis for SiO2 film (9.2 nm thick) on Si wafer by changing the range of initial ending points or a shape of Voigt function in the active Shirley method. It demonstrated that the thickness of the SiO2 film was estimated at 9.71 ± 0.14 nm from noisy Si 2p peaks in the commonly-used range.