The importance of silicon nitride (Si3N4) prepared by the chemical vapor deposition (C VD) technique is discussed briefly. A computer code was used to calculate CVD phase diagrams useful for the preparation of this material. Theoretical deposition efficiencies and gaseous phase compositions are also reported. The reactants include NH3/SiH4, NH3/SiH2Cl2, NH3/SiCl4, and NH3/SiF4. The effect of N2, H2, and Ar additions, as well as the system pressure, are evaluated. The results are compared with experimental data from the literature.

Thermodynamic Calculations for the Chemical Vapor Deposition of Silicon Nitride

Chemical vapor deposition of silicon carbide for coated fuel particles

Physicochemical properties of SiC-based ceramics deposited by low pressure chemical vapor deposition from CH3SiCl3H2

SiC films were chemically vapor deposited onto graphite substrates using methyltrichlorosilane (MTS, CH3SiCl3) as a source and argon or hydrogen as diluent gases to investigate the effect of each diluent gas on growth behavior and characteristics. Each diluent gas used had a relative difference in deposition rate within a certain temperature region. Such growth characteristics of the SiC films as preferred orientation, microstructure, and chemical composition varied remarkably with the diluent gas used. Microhardness and surface roughness were compared for SiC films prepared using the different diluent gases.

Effect of Diluent Gases on Growth Behavior and Characteristics of Chemically Vapor Deposited Silicon Carbide Films

Stabilization of a perovskite structure was attempted by replacing Mg for Zn in Pb(Zn1/3Ta2/3)O3. System powders were prepared using a B-site precursor method by reacting PbO with separately-prepared precursor compositions. Effects of the substituent Mg concentration on perovskite phase developments and subsequent changes in dielectric properties were investigated, as a function of measurement frequency. Phase transition modes reflected in the dielectric constant spectra were analyzed in terms of diffuseness exponent and degree of diffuseness. Internal microstructures of the ceramics were examined, and correlations with perovskite phase contents and dielectric properties are discussed.

K. Iwamoto

Papers

Formation of carbon-excess SiC from pyrolysis of CH3SiCl3