Formation of silicon carbide at low temperatures by chemical transport of silicon induced by atmospheric pressure H2/CH4 plasma

Using atmospheric pressure, very high-frequency (VHF) plasma, silicon carbide (SiC) films were formed on single-crystal Si(001) substrates from a hydrogen (H2) and methane (CH4) mixture. The H2/CH4 plasma etched the cooled surface of a Si-coated electrode, generating SiHn species, and transported them to the heated substrate surface with interactions with CHn species generated from the decomposition of CH4 molecules. By virtue of the carbonization of the substrate surface in the beginning of deposition, a (001)-oriented 3C–SiC film could be formed at a substrate temperature (Tsub) as low as 300°C, although the film-forming reaction was more enhanced at the higher Tsub due to the smaller etching rate of the growing SiC film by atomic hydrogen. At Tsub = 130°C, however, the full crystallization of the film did not occur, resulting in the deposition of a polycrystalline 3C–SiC film with the poorer crystallinity. The optical emission spectra of the plasma revealed that the Si substrate was etched by atomic hydrogen in addition to the Si-coated electrode at 130°C.