Study of thermal diffusion between Al O and Al thin films

Alumina and aluminum thin films were deposited by physical evaporation methods obtaining a set of five samples of Al2O3 130 nm.rAl 130 nm.rglass. Samples were heat treated in vacuum between room temperature and 6008C. After annealing, samples were characterized by means of Auger electron spectroscopy AES., scanning electron microscopy SEM., X-Ray diffraction XRD.and stylus profilometry. All samples present a fairly large amount of aluminum in the alumina layer. Samples heat-treated between room temperature and 4008C show an interface roughness between layers, which obscures thermal diffusion. The diffusion coefficient at 5008C, for metallic aluminum is Ds1.5=10y15 cm2 sy1. At a temperature of 6008C the interface width between the deposited layers increases, resulting in an uniform layer with all components mixed. q1999 Elsevier Science B.V. All rights reserved.