Preparation of bismuth silicate films on Si wafer metalorganic chemical vapor deposition

Thin films of crystalline Bi4Si3O12 were prepared by metalorganic chemical vapor deposition for use as capacitor layers in DRAM or buffer layers for epitaxial growth of various oxide crystals on Si wafer. This film was formed at 650-820°C by the reaction between SiO2 layer on Si and mixed gas of Bi vaporized from triphenylbismuth and O2. The films deposited at 760°C had a flat and homogeneous surface with a preferred orientation of crystals perpendicular to the film surface. The remaining SiO2 was observed between deposited film and Si. For the formation of homogeneous film without underlying SiO2, the growth rate of bismuth silicate should be faster than the deposition rate of Bi2O3 as well as the oxidation rate of Si substrate.