In this paper, we study the kinetics of carbon incorporation in Si1-x-yGexCy/Si(001), by ultra high vacuum-chemical vapor deposition. Layers were grown with a Ge content of 3% and substitutional C content up to 1.7%. All the layers were tensily strained. Using a simple model derived from the commonly accepted growth mechanism for silicon from SiH4, we deduced an expression for the growth rate as a function of the temperature and the SiH4 partial pressure. A qualitative model for surface roughening due to carbon incorporation is proposed. From that, we observed that the surface diffusion of carbon adatoms is limited by hydrogen coverage.