Investigation of oxidation process on plasma treated thin Al-films by GIXRand GIXRD

The sensitivity of grazing incidence X-ray reflectometry (GIXR) for amorpho us as well as crystalline layers and for layer formations in the nm-range c ombined with information about structural states by grazing incidence X-ray diffractometry (GIXRD) enable these methods to study interfaces and surfac e layers. Thin aluminium layers (30-60 nm) were deposited on Si by thermal evaporation. These Al-layers were plasma oxidized for 5 h with interruption s every hour. The plasma treatments were carried out in a 2.45 GHz microwav e discharge (SLAN-slot antenna) with different plasma types (Ar, O-2) at lo w temperatures. In this way a thin oxide layer additional to the native alu mina on the top was formed. The properties of the oxide layers such as thic kness, roughness and density were studied by GIXR. The chemical composition was investigated by GIXRD and XPS. Ln addition AFM was used for surface to pography observations. All these methods were applied before and after the plasma treatment. The properties of the thin Al-oxide layers were found to depend on the type of plasma but in all cases plasma leads to a smoothing o f the films as well as an increasing of the thickness of the upper alumina layer. (C) 1999 Elsevier Science S.A. All rights reserved.