Effect of gas pressure on hydrogenated amorphous silicon carbide films by hot-wire CVD

Hydrogenated amorphous silicon carbide (a-Si/sub 1-x/C/sub x/:H) films were prepared by hot-wire chemical vapor deposition (CVD) using methane as a carbon source at a low tungsten temperature of 1400/spl deg/C, and the effect of gas pressure on the film properties and structure was investigated. The infrared absorption spectra revealed that Si-C bonds increased with increasing gas pressure from 1 to 4 Torr. Consequently, the optical band gap increased from 1.8 to 2.2 eV. The deposition rate was 1.2 nm s/sup -1/ at 4 Torr and higher than that in plasma-enhanced CVD deposition by about one order of magnitude. It was found that a-Si/sub 1-x/C/sub x/:H films with an optical band gap over 2.0 eV could be easily prepared by control of gas pressure even at a low tungsten temperature of 1400/spl deg/C and at a higher deposition rate.