Structure of alpha-Al2O3(0001) surface and Ti deposited on alpha-Al2O3(0001) substrate; CAICISS and RHEED study

The structure of the alpha-Al2O3(0001) surface and Ti deposited on the alph a-Al2O3(0001) substrate has been investigated using co-axial impact collisi on ion scattering spectroscopy and reflection high energy electron diffract ion. It has been found that the Al2O3 (0001) surface is terminated by an Al layer, as predicted by several theories. The coexistence of Al and O termi nated domains has not been observed. In the thickness range of the overlaye r Ti films from 4 to 40 monolayers on Al2O3 (0001), the growth mechanism of the deposited films has been revealed to be consistent. The structure of a thick Ti film formed epitaxially on the substrate corresponds to alpha-Ti, while in the initial stage the adsorbed Ti atoms are thought to succeed to the periodicity of the Al2O3 (0001) surface. (C) 1999 Elsevier Science B.V . All rights reserved.