Microstructure of (Ba, Sr)TiO3 thin films deposited by physical vapor deposition at 480 °C and its influence on the dielectric properties

The orientation and microstructure of (Ba, Sr)TiO3 (BST) deposited via physical vapor deposition at 480 °C was studied using x-ray diffraction, atomic force microscopy, and transmission electron microscopy. Annealing Pt/BST (previously annealed at 400 °C) at 800 °C in O2 results in grain growth, enhancement of the {100} texture and a 20% increase in the dielectric constant. The 400 °C annealed films become more textured in the {100} orientation as film thickness is increased. Finally, it appears that an interfacial capacitance, rather than the “bulk” dielectric constant limits the total capacitance density of the films.