Analysis of the formation of BaTiO₃ island deposited on (111) InSb by metalorganic chemical vapor deposition at low temperature

Islands of BaTiO₃ in a thin film deposited on a (111) InSb substrate by metalorganic chemical vapor deposition at a temperature of 300°C were investigated. Refractive index measured by ellipsometer using a He-Ne laser was 1.95, which is nearly the same value as that of amorphous BaTiO₃ with microcrystals. X-ray diffraction peaks showed the deposit to be mostly amorphous and partly crystalline having the 〈110〉BaTiO₃ direction normal to the (111) InSb. Transmission electron microscopy results showed that partially epitaxial BaTiO₃ islands with periodic misfit dislocations had been formed at the interface between amorphous BaTiO₃ thin layer and the (111) InSb substrate. These BaTiO₃ islands on the (111) InSb substrate formed at a low growth temperature were three-dimensional nuclei which were closely associated with surface irregularities of the (111) InSb substrate.