Formation of Silicon Carbide Powders by the Vapor Phase Reaction of the SiH₄-CH₄-H₂ System

Abstract

The formation of silicon carbide powders by the vapor phase reaction of the SiH₄-CH₄-H₂ system was studied at the temperature of 1000-1400°C. The powder products consisted of β-SiC and silicon at low reaction temperatures, but they became pure SiC at 1400°C. The SiC particles were spherical and hollow. The particle sizes were 0.01μm to 0.15μm, and they decreased when the reactants were heated sharply. On the other hand, solid SiC particles, were produced under the conditions that the reactants were heated very sharply and the effective reaction temperature was increased.
It is concluded that the formation of hollow SiC particles from the SiH₄-CH₄-H₂ system occurs by a two-step process: the formation of silicon particles, by the pyrolysis of SiH₄ and their carburization with methane. The solid SiC particles obtained when the effective reaction temperature was increased, were considered to be formed by the nucleation ofSiC and its growth.