Preparation and characterization of Ce-doped BaTiO3 thin films by r.f. sputtering

Ce-doped BaTiO3 thin films prepared on silicon-platinium by r.f. sputtering has been investigated. BaTiO3 doped with 5.5 mol%CeO2 thin film was deposi ted at 550 degreesC substrate temperature in an Ar atmosfere. The crystal s tructure and shape were examined by X-ray diffraction and scanning electron microscopy with EDAX. Analysis by X-ray diffraction patterns show that the crystalline film with a cubic structure of BaTiO3, was obtained. The surfa ce morphology (roughness, the grain size and the droplet size) of the thin film surface was examined by atomic force microscopy (AFM). The grain size is about 160 nm, the droplet size is about 0.675 mum and the roughness is 3 6.88 nm. EDAX analysis established a composition of the film to be identica l with that of the target (BaTiO3 doped with 5.5 mol%CeO2). The broad peak in the capacitance versus temperature curve at the Curie point indicate tha t the r.f. sputtered Ce-doped BaTiO3 film is ferroelectric. The values of t he capacitance of the thin film at 1 KHz were found to be 86 pF and the los s dielectric was tan delta = 0.0875. The film exibits a dielectric anomaly peak at 23 degreesC showing ferroelectric to paraelectric phase transition. (C) 2001 Kluwer Academic Publishers.