AL2O3+X AL INTERFACE FORMATION BY PROMOTED OXIDATION USING AN ALKALI-METAL AND REMOVAL OF THE CATALYST/

We report the effect of Na overlayers on the oxidation of Al thin film s by core level photoemission spectroscopy using synchrotron radiation . The presence of a Na monolayer enhances the aluminum room temperatur e oxidation rate by 4 orders of magnitude with formation of alumina as Al2O3 and Na oxides, possibly as aluminates. Furthermore, the Na cata lyst could be desorbed from the surface by a rapid thermal annealing a t temperatures below 300-degrees-C, leading to the growth of aluminum oxides having a binding energy larger than stoichiometric Al2O3. It in dicates the formation at the surface of Al oxides having higher oxidat ion states.