Surface Morphologies of BaTiO3 Thin Films by Atomic Force Microscopy

Surface morphologies of BaTiO3 thin films have been studied by atomic force microscopy (AFM). The films on (111)InSb, indium tin oxide (ITO)-coated glass and (100)Si substrates are deposited by in-situ metalorganic chemical vapor deposition (MOCVD) at different deposition temperatures of 300°C, 400°C and 600°C, respectively. AFM under ambient conditions showed that the BaTiO3 film deposited on the ITO-coated glass had a smooth surface consisting of large hemispherical grains, while the film on (100)Si had a slightly rough surface with <110> textured rectangular grains. As-grown film on the (111)InSb substrate was in the amorphous phase except near the interface, resulting in a rough surface. Our results of dependence on the kind of substrates and growth temperature suggest that the surface morphology of the as-grown films is strongly influenced by the crystallinity and growing characteristic of the film. For low-temperature growth below the deposition temperature of 600°C, surface roughness of the BaTiO3 film is strongly dependent on growth temperature rather than crystallinity of the films related to substrates.