Effect of different buffer layers on the microstructure and dielectric properties of BaTiO_3 thin films grown on Si substrates

摘要

Ferroelectric BaTiO_3 films were deposited on BaTiO_3 and Pt-buffered Si (1 00) 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 (100)-orientation with better crystallization, larger grain size, and smoother surface, while those on Pt show (111)-oriented structure with coarser surface morphology, due to the easier nucleation of BaTiO_3 (100) planes at the (100) 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.