Oxidation of Polycrystalline Copper Thin Films at Ambient Conditions

Qualitative and quantitative studies of the oxidation of polycrystalline copper (Cu) thin films upon exposure to ambient air conditions for long periods (on the order of several months) are reported in this work. Thin films of Cu, prepared by thermal evaporation, were analyzed by means of X-ray photoelectron spectroscopy (XPS) to gain an understanding on the growth mechanism of the surface oxide layer. Analysis of high-resolution Cu LMM, Cu2p3/2, and O1s spectra was used to follow the time dependence of individual oxide overlayer thicknesses as well as the overall oxide composite thickness. Transmission electron microscopy (TEM) and spectroscopic ellipsometry (SE) were used to confirm the results obtained from…