Characterization of the surface and interface species formed during the oxidation of aluminum

The reaction of oxygen with polycrystalline Al has been studied at room temperature using a wide variety of analytical tools (AES, XPS, ARXPS and FA). According to previous studies on Al oxidation, the interaction of oxygen with aluminum occurs in three stages: chemisorption, a fast initial oxidation mechanism with oxygen incorporation and slow growth of a compact oxide film. In the present work it is shown that the application of FA to the Al LVV and O KLL spectra allows the identification of two different chemical species, in addition to Al-0, related to chemisorption and oxide formation, respectively. Furthermore, it has been found that ARXPS results are consistent with the formation of a chemisorbed phase consisting of single-layer oxygen islands which grow to completely cover the surface at around 10 L, prior to the formation of oxide islands which represents the first stage of the interaction of oxygen with the substrate. The second stage is characterized by the formation of oxide islands which grow to cover the surface above 1000 L. The third stage is characterized by a slow growth of a compact oxide film beyond 1000 L.