Effect of different buffer layers on the microstructure and dielectric properties of BaTiO 3 thin films grown on Si substrates

Abstract

Ferroelectric BaTiO 3 films were deposited on LaNiO 3 and Pt-buffered Si (1 0 0) substrates by radio frequency sputtering. The effect of different buffer layers on the corresponding orientation, crystallization, dielectric and leakage current properties of BaTiO 3 films was comparatively investigated. X-ray diffraction and atomic force microscope analysis demonstrate that the BaTiO 3 films on LaNiO 3 exhibit highly (1 0 0)-orientation with better crystallization, larger grain size, and smoother surface, while those on Pt show (1 1 1)-oriented structure with coarser surface morphology, due to the easier nucleation of BaTiO 3 (1 0 0) planes at the (1 0 0) LaNiO 3 surface. Electrical measurements indicate that the BaTiO 3 films on LaNiO 3 show larger dielectric constant and also higher leakage current density than those on Pt. The difference in electrical properties for the two BaTiO 3 films is suggested to be closely related to the various grain size and structural orientation on different buffer layers.