Mechanisms of SiC growth by alternate supply of SiH2Cl2 and C2H2

Heteroepitaxial growth of 3C-SiC on Si(001) substrate has been realized by the use of a hot-wall type LPCVD with an alternating supply of acetylene (C2H2) and dichlorosilane (SiH2Cl2) in the temperature range 1000–1050°C. By synchronizing hydrogen (H2) supply with C2H2 supply, the reduction of SiCl2 molecules on the surface of the substrate during SiH2Cl2 supply was suppressed, resulting in the realization of the self-limiting process of SiCl2 adsorption in the SiC growth process. The growth rate of 3C-SiC was independent of the temperature, the flow rate of the SiH2Cl2 and the duration of the SiH2Cl2 supply. To suppress the reduction of the SiCl2 molecules during the SiH2Cl2 supply seems to be a necessary condition to realize layer-by-layer growth of SiC. Since residual C2H2 molecules hinder the SiCl2 molecules from being adsorbed on the substrate, the C2H2 molecules on the surface of the substrate may give rise to a suppression of SiC growth.