Modification of semiconductive BaTiO3 film and its electrical properties

Nonlinear V-I characteristics were observed in semiconductive BaTiO3 film heated at 550 degrees C for 2 h in air. The temperature dependency of the resistivity appeared to be the minimum near 120 degrees C for this heat treatment. It was estimated from the keeping time dependency of the resistivity that the oxidation in this film occurs first at the grain boundary between columnar grains and then goes to the inner of the grains. The structure made up of both the semiconductive grains and the oxidized interfaces with high resistivity was considered to generate these properties. Nonlinear V-I characteristics also appeared from diffusion of Bi element from the surface of the BaTiO3 film. These results show the possibility of the generation of new properties by the modification of grain boundaries between columnar grains of semiconductive BaTiO3 film, which is comparable to that of the sintered body of semiconductive BaTiO3-based functional ceramic.