Interface phase transformations in 1 mu m aluminum+ 1 mu m gold thin film couples upon 24-h isothermal annealing at 125, 150 and 175 degrees C were studied. It is shown that temperature change does not affect the type of phases formed but only alters their growth rates. The layered structures consisting of multiple intermetallics were identified by X-ray diffraction and electron microscopy. Interface tracking using secondary ion mass spectroscopy depth profiling showed that Au is the predominant diffusant in this system. Intermetallic thickness growth measurements were made and the activation energy calculated to be 33.602 kJ/mol. (C) 2007 Elsevier B.V. All rights reserved.