RF-プラズマ法によるSiC, Si3N4粉体の合成

By the RF-plasma method, preparation of silicon carbide and silicon nitride powders from alkoxysilanes (Si(OC2H5)4, (CH3)2Si(OC2H5)2 and (CH3)2Si(OCH3)2) and from SiCl4-NH3 system, respectively, was studied. In the preparation of silicon carbide, the reaction product consisted of β-SiC, free carbon and silicon oxide. The amount of SiC in the powder product increased with rising reaction temperature or with increasing [H2]. The amount of SiC increased with decreasing C/Si ratio in alkoxysilanes and was estimated to reach 100% when the C/Si ratio is around 3. In the preparation of silicon nitride, the reaction product was white and non-crystalline powders with a particle size of 0.01-0.02μm. The composition of powders was virtually independent of [NH3] and close to that of Si3N4. Heat treatment at 1550°C was necessary to obtain the crystalline α-Si3N4.