Characterization of polycrystalline SiC films grown by HW-CVD using silicon tetrafluoride

SiC films were synthesized by hot-wire chemical vapor deposition using a tungsten filament and a gas mixture of SiF4 and CH4. The etching of the substrate instead of the film growth occurred on the samples prepared using only source gases without H2 dilution. The atomic or molecular hydrogen was believed to control the density of radicals containing F in a gas phase or on a growth surface. Polycrystalline 3C-SiC(111) films were successfully obtained at substrate temperatures lower than 500 °C by using H2 dilution. The growth mode limited by source-gas supply was found to be important to obtain polycrystalline SiC films. The SiC film grown at higher deposition pressure was amorphous and contained no Si–Hx bonds but 6% fluorine. In SiF4/CH4/H2 system, the radicals containing F are considered to play very important roles in the reactions both on a growth surface and in a gas-phase.