HIGH-RATE REACTIVE DE MAGNETRON SPUTTER-DEPOSITION OF AL2O3 FILMS

Aluminum oxide films were produced by reactive de magnetron sputtering of Al in Ar+O-2. The composition of the films was characterized by Ru therford backscattering measurements. Stoichiometric films possessed e xcellent optical properties with a refractive index of similar to 1.6 for visible and near-infrared light. It was possible to produce stoich iometric films while keeping the target in the metallic mode of operat ion; the resulting deposition rate was 23 nm min(-1), as compared to 0 .95 nm min(-1) for films grown from an oxidized target. An O/Al arriva l rate ratio exceeding similar to 17 was required for stoichiometric f ilms to be grown at room temperature. The success of the present high- rate deposition strategy hinges on the use of a suitable deposition sy stem geometry--including a large target-to-substrate distance and a sm all target size--and on the use of sufficient Ar pressure. Monte Carlo simulations are presented; they can be reconciled with our empirical data. (C) 1998 American Vacuum Society.