We use infrared absorption spectroscopy (IRAS) in the multiple internal reflection geometry to investigate the carbon incorporation during chemical vapor deposition of SiC on Si(1 0 0) using methylsilanes, SiHx(CH3)(4-x) (x = 1-3). We have measured IRAS spectra in the Si-H stretching vibration region of the Si(1 0 0) surface that was dosed with methylsilanes at temperatures ranging from 300 to 500 degreesC. IRAS data demonstrate that at temperatures below 400 degreesC, methylsilane is thermally decomposed to form a doubly occupied dimer (DOD. =HSi-SiH=) and a mixed adatom dimer (=HSi-SiH=). At higher temperatures, carbon atoms that are released from the methyl group, attack the backbonds of surface Si atoms to generate amorphous carbon-incorporated layers that include Si atoms having two or three C atoms bound to them. It is found that the carbon incorporation is enhanced with the increase of the number of methyl groups of methylsilane.