for baseline correction, peak detection, peak integration and peak fitting. For the as-deposited L-CVD SnO 2 thin films a mixture of SnO and SnO 2 was observed, while for the oxidized L-CVD SnO 2 thin films the domination of SnO 2 was determined. Origin provides powerful and versatile tools such as Peak Analyzer, Quick Peaks Gadget, Integration Gadget, etc. The oxidation states of L-CVD SnO 2 thin films in both cases were confirmed by the shape analysis of corresponding XPS O1s and Sn3d 5/2 peaks using the decomposition procedure. Almost the same relative concentration / of L-CVD SnO 2 thin films has been obtained after long term exposure to air. After in situ oxidation at high temperature (800 K) the relative concentration / increases to 1.95 ± 0.05 which corresponds to the almost stoichiometric SnO 2. As-deposited L-CVD SnO 2 thin films exhibit evident nonstoichiometry with the relative concentration / equal to 1.29 ± 0.1. Spectral resolution is on the order of 0. Quantitative peak-area ratios for the three types of carbon in polyethylene terephthalate (PET) polymer can be seen below. Moreover, the ageing effect was also studied in order to check the influence of ambient oxidation. XPS is suitable for the analysis of conductors and insulators such as polymers (see example below). In this paper we present the results of XPS study of the surface chemistry of L-CVD SnO 2 thin films onto Si(100) before and after subsequent additional oxidation.