Atomic Layer Deposition of SrTiO3 Thin Films from a Novel Strontium Precursor-Strontium-bis(tri-isopropyl cyclopentadienyl)

Abstract

Strontium titanate thin films were grown by atomic layer deposition (ALD) at 250–325 °C from the novel strontium compound, strontium bis(tri-isopropyl cyclopentadienyl), titanium tetraisopropoxide, and water. Though completely self-limiting, deposition of strontium could not be achieved because of some minor decomposition of the strontium compound. This decomposition was slow enough to ensure that good control of film stoichiometry was obtained by controlling either the (Sr-O)/(Ti-O) pulsing ratio, or the strontium precursor exposure time. The films were polycrystalline and strongly oriented in the (100) direction. After annealing at 500 °C in air, the films with the optimal composition were found to have measured permittivity values of around 180.