Atomic layer deposited SrTiO3 (STO) thin films were grown using Sr(C11H19O2)(2) and Ti(Oi-C3H7)(4) with a remote plasma activated or thermal H2O vapor as oxidant at growth temperatures ranging from 190 to 270 degrees C. The as-grown films were amorphous and showed a low effective dielectric constant of similar to 20 with a low leakage current density (< 10(-7) A/cm(2) at 1 V). The chemical binding status of the Sr ions varied with the degree of crystallization of the STO film. A reasonable film growth rate and stoichiometric cation composition were obtained when the vaporization temperature of Sr-precursor was < 200 degrees C with the thermal H2O vapor. The low density of the as-grown film induced a large shrinkage in the film thickness which caused microcracking of the crystallized films during postannealing, even with the increased H2O supply. Adoption of thin (similar to 5 nm) crystallized seed layer before the main layer STO growth improved the microstructure after the crystallization and the leakage current performance. As a result of the process optimization, the best electrical properties of an STO film grown on a Ru electrode were 0.45 nm for the equivalent oxide thickness and 1 x 10(-3) A/cm(2) for the leakage current density at 1 V. (c) 2007 The Electrochemical Chemistry.