MOCVD growth of barium–strontium titanate films using newly developed barium and strontium precursors

Abstract

We report on metal-organic chemical vapor deposition (MOCVD) of the Ba x Sr 1 − x TiO 3 (BST) films (with x ≈ 0.5) on SrTiO 3 substrates. This research comprises the development of new chemical precursors, modification of the MOCVD apparatus towards stoichiometric oxide growth and undesirable phase suppression, as well as establishing optimum growth conditions. The grown BST films were characterized by the set of experimental techniques, including high-resolution X-ray diffraction (HRXRD) and high-resolution scanning electron microscopy. The newly synthesized organo-metallic precursors exhibit better properties than the available precursors and, in particular, show low melting points of about 80 °C. By using these precursors, we succeeded to grow sub-micron thick BST films of high crystalline quality. Optimum growth temperature was found to be 740 °C. The symmetric and asymmetric HRXRD profiles, as well as wide-angle X-ray diffraction scans, taken from the films grown under optimal conditions, reveal epitaxial orientation relations between the film and the substrate.