Preparation of Bismuth Silicate Films on Si Wafer by Metalorganic Chemical Vapor Deposition

Abstract

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.