Plasma-enhanced atomic layer deposition of SrTa2O6 thin films using Sr[Ta-OC2H5)(5)(OC2H4OCH3)](2) as precursor

SrTa2O6 thin films were prepared by plasma-enhanced atomic layer deposition using strontium bis[tantalum(pentaethoxy)(2-methoxyethoxide)], Sr[Ta(OC2H5)(5)(OC2H4OCH3)](2), and an O-2 plasma. The thickness of the SrTa2O6 thin film increased linearly with the number of cycles employed, and the deposition rate at 250 degreesC was about 0.05 nm per cycle. The Sr/Ta ratio in the SrTa2O6 films decreased slightly with increasing deposition temperature. SrTa2O6 films prepared at 250 degreesC showed a stoichiometric composition. The surface morphology of an as-deposited film at 250 degreesC was very smooth, with an rms roughness of about 0.23 nm. Furthermore, the morphology of the film remained unchanged after high temperature annealing. From the relationship between the capacitance equivalent thickness (CET) of the film and the physical thickness of SrTa2O6, the CET for the interfacial layer and the dielectric constant of SrTa2O6 were calculated to be approximately 1.75 nm and 30.5, respectively. (C) 2004 The Electrochemical Society.