Microstructural Investigation of Ba 0.7 Sr 0.3 TiO₃ (BST) Thin Films on Various Electrodes and Buffers

Ba 0.7 Sr 0.3 TiO₃ (BST) thin films were deposited simultaneously on various electrodes and buffers by the sputtering technique. When the substrate temperature was varied, the BST thin film on each electrode showed good crystallinity above 550℃ as revealed by X-ray diffraction measurements. The surface morphology, determined by atomic force microscopy, indicated that the roughness of BST thin films on RuO₂ was substrate dependent. However, BST thin films on Ru electrodes are smoother and showed no substrate dependence, probably because the precursor surface diffusion length was greater than the sinusoidal perturbations of the wavelength.