Preparation and properties 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 deposited at 550 degreesC substrate temperature in Ar atmosfere. The crystal structure 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 surface 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 36.88 nm. EDAX analyse established a composition of the film identicaly with that of target (BaTiO3 doped with 5.5 mol.%CeO2). The broad peak in the capacitance versus temperature curve at Curie point indicate that the r.f. sputtered Ce-doped BaTiO3 film is ferroelectric. The values of the capacitance of the thin film at 1 KWz were found to be 86 pF and the loss dielectric was tan delta =0.0875. The film have presented dielectric anomaly peak at 23 degreesC showing ferroelectric to paraelectric phase transition.