Al2O3/Al films (period thickness Lambda=20, 40 nm) were deposited onto (10 0) silicon substrate by reactive r.f. sputtering for substrate temperatures (T-s) ranging from -90 to 600 degreesC. Secondary ion mass spectrometry demonstrated the deposition of Al2O3/Al stratified thin films with the generation of periodic signals. X-ray reflectometry confirmed the periodicity with the presence of Bragg peaks in the experimental patterns. Nevertheless, the multilayered character of Al2O3/Al films is less and less pronounced as T-s increases. At low T-s, the relevant parameter to account for the absence of abrupt interfaces is the roughness of layers due to the aluminium layers, while at high T-s, the chemical interdiffusion clearly dominates. (C) 2003 Elsevier B.V. All rights reserved.