X-RAY STUDIES OF AL/AL2O3 MULTILAYERED FILMS

Multilayered Al/Al2O3 films were prepared by vacuum evaporation. Each film is composed of alternately deposited aluminium and Al2O3 layers with the same layer thicknesses of 50, 100, 500 or 1000 nm. All films have the same total thickness which is about 2-mu-m. Two kinds of substrate-single-crystal silicon and glass-were used to study the influence of substrate on the structure and crystal defects in films. The microstructure and dislocations in the aluminium component were studied by X-ray diffraction profile analysis based on Wilkens' theory and Wang's method. The results show that the domain size in aluminium grains increases with increasing thickness of the single layer in all cases but the dislocations are distributed differently in differently oriented grains. The dislocation density decreases with increasing single-layer thickness but the absolute value is much larger for silicon substrates than for glass substrates. Two mechanisms of dislocation production and multiplication are suggested: thermal stress and atomic misfit on the interface. For the atomic structure of interface, the "lock-in" model is preferred to the coincident-site lattice model.