The Hot Wire (HW) Cell method was applied to grow epitaxial Si films at a substrate temperature of 200 degreesC. C2H2 gas was added to this system and C containing epitaxial Si films were also obtained. After annealing the films at 600-700 degreesC, the vibration mode at 607 cm(-1), which indicated the presence of the C atoms located at the Si substitutional sites, was observed in Fourier transform infrared absorption and Raman scattering spectroscopy. The X-ray diffraction peak of the annealed films shifted to a,greater extent compared to the substrate, which indicated the decrease in the lattice constant of the epitaxial layer. The carbon composition was controlled by changing the partial pressure of the C2H2 gas and we successfully obtained 0.8 at.% substitutional carbon composition.