RF-sputtering deposition of Al/Al2O3 multilayers

In order to study mechanical and electrical behaviour of nanoscale laminate d materials, Al/Al2O3 multilayers have been deposited by reactive rf-sputte ring for substrate temperature T-8 ranging from -80 degrees C to 600 degree s C. Polycrystallised aluminium films exhibit a rough surface, with grain s ize increasing with substrate temperature. Alumina films are amorphous, wit h smooth surface, except a high temperature. Al/Al2O3 multilayers were elab orated by lowering period thickness from 40 to 2 nm, keeping a 1:1 Al/Al2O3 ratio. As metal films, multilayers present a granular surface. SEM cross-s ection observations did not point out any laminated structure. Nevertheless , X-ray reflectometry have demonstrated the multilayering character of film s with emergence of different Bragg peaks. This character seems to decrease with increasing temperature as the number of peaks is gradually reduced fr om T-s = -80 degrees C to T-s = 600 degrees C. This may be due to the incre asing roughness of aluminium layers with temperature, added to a possible d iffusion of oxygen. (C) 1998 Elsevier Science S.A. All rights reserved.