Aluminum oxide films were produced by reactive de magnetron sputtering of Al in Ar+O-2. The composition of the films was characterized by Rutherford backscattering measurements. Stoichiometric films possessed excellent optical properties with a refractive index of similar to 1.6 for visible and near-infrared light. It was possible to produce stoichiometric films while keeping the target in the metallic mode of operation; 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 arrival rate ratio exceeding similar to 17 was required for stoichiometric films to be grown at room temperature. The success of the present high-rate deposition strategy hinges on the use of a suitable deposition system geometry--including a large target-to-substrate distance and a small target size--and on the use of sufficient Ar pressure. Monte Carlo simulations are presented; they can be reconciled with our empirical data.