TRANSMISSION ELECTRON-MICROSCOPY OBSERVATION OF THE INTERFACIAL REACTION BETWEEN A METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION BATIO3 THIN-FILMAND A (100)MGO SUBSTRATE

Cross-sectional and plan-view transmission electron microscopy were us ed to characterize a BaTiO3 thin film deposited on a (100) MgO single- crystal substrate at 1000 degrees C. The major observations were as fo llows: interdiffusion between the film and substrate; a large number o f antiphase boundaries in the BaTiO3; a two-phase microstructure in th e film composed of perovskite BaTiO3 and a second nonperovskite phase, Ba2MgTi5O13 (2:1:5); and a well-defined orientation relationship betw een the 2:1:5 and BaTiO3 phases. We propose a mechanism for the format ion of the 2: 1 :5 phase based on the similarities between the crystal structure of this phase and the structure of (210) antiphase boundari es in BaTiO3.