We were successful in growing a uniform flat Al2O3 film on the Cu-9%Al(111) surface using the improved cleaning process, low ion energy and short time sputtering. The growth of ultra-thin film of Al2O3 on Cu-9%Al was investigated using Auger electron spectroscopy (AES) and a scanning electron microscope (SEM). The Al2O3 film whose maximum thickness was about 4.0 nm grew uniformly on the Cu-9%Al surface. The Al and O KLL Auger peaks of Al2O3 film shifted toward low kinetic energy, and the shifts were related to Schottky barrier formation and band bending at the Al2O3/Cu-9%Al interface. The thickness of Al2O3 film on the Cu-9%Al surface was controlled by the oxygen exposure. (C) 2004 Elsevier B.V. All rights reserved.