Oxidation of cobalt as investigated by x-ray photoelectron spectroscopy

Thin films of cobalt (about 20 nm) were deposited on a silicon ⟨100⟩ substrate. The deposition was carried out using the e-beam technique. The films were oxidized under two different conditions: in vacuum and in a quartz tube furnace. The elemental cobalt and the two oxidized samples were characterized by the technique of x-ray photoelectron spectroscopy. Magnesium Kα radiation (1253.6 eV) was used as the source of the x-ray excitation. The spectral data in the cobalt 2p, 2s, 3s, 3p, Auger LMM regions, oxygen 1s region, and carbon 1s regions were recorded under a high resolution mode. The sample oxidized in vacuum showed features distinct from that oxidized in the quartz tube furnace. The data will serve as a comparison for the cobalt oxides formed under different processing conditions.