The effects of oxygen partial pressure on BST thin films deposited on multilayered bottom electrodes

Ba0.5Sr0.5TiO3 (BST) thin films have been deposited by r.f. magnetron sputtering on silicon and platinum-coated silicon substrates with different buffer and barrier layers. BST films deposited on Si/SiO2/SiN/Pt and Si/SiO2/Ti/TiN/Pt multilayer bottom electrode have been used for the fabrication of capacitors. XRD and SEM studies were carried out for the films. It was found that the crystallinity of the BST thin film was dependent upon oxygen partial pressure in the sputtering gas. The role of multilayered bottom electrode on the electrical properties of Ba0.5Sr0.5TiO3 films has been also investigated. The dielectric properties of BST films were measured. The results show that the films exhibit pure perovskite phase and their grain sizes are about 80-90 nm. The dielectric properties of the BST thin film on Si/SiO2/Ti/TiN/Pt electrode was superior to that of the film grown on Si/SiO2/SiN/Pt electrode.