A method employing atomic layer deposition rapid vapor deposition (RVD) conformally deposits a dielectric material on small features of a substrate surface. The resulting dielectric film is then annealed using a high density plasma (HDP) at a temperature under 500.degree. C. in an oxidizing environment. The method includes the following three principal operations: exposing a substrate surface to an aluminum-containing precursor gas to form a substantially saturated layer of aluminum-containing precursor on the substrate surface; exposing the substrate surface to a silicon-containing precursor gas to form the dielectric film; and annealing the dielectric film in a low temperature oxygen-containing high density plasma. The resulting film has improved mechanical properties, including minimized seams, improved WERR, and low intrinsic stress, comparable to a high temperature annealing process (.about.800.degree. C.), but without exceeding the thermal budget limitations of advanced devices.