INFLUENCE OF SUBSTRATE ANNEALING ON THE EPITAXIAL-GROWTH OF BATIO3 THIN-FILMS BY METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION

BaTiO3 thin films were deposited by metal-organic chemical vapor depos ition at 840 degrees C on two differently treated (100) MgO single cry stal substrates, One MgO substrate was only mechanically polished and the other substrate was polished and then annealed at 1100 degrees C f or 4 h in oxygen, Observation by transmission electron microscopy show ed that the BaTiO3 thin film deposited on the unannealed substrate was fine-grained and that the whole film was epitaxial (100) in nature, I n contrast, the film deposited on the annealed substrate consisted of large, (100)-oriented, epitaxial grains within which were distributed (110)-oriented grains with random in-plane orientations. These differe nces in BaTiO3 films deposited on differently treated substrates are d iscussed with reference to the surface structure of the MgO substrate and nucleation kinetics of BaTiO3 thin films on MgO.