Epitaxial Si films have been grown by the mercury sensitized photo-CVD method using a SiH4/H-2 gas mixture with and without SiH2Cl2 at a substrate temperature lower than 200-degrees-C. The effect of SiH2Cl2 on low-temperature Si epitaxy was investigated. The structural properties of the obtained films were characterized by reflection high-energy electron diffraction (RHEED), IR and Raman spectroscopy. It was found that the film quality was improved by the addition of SiH 2Cl2. The most probable role of SiH2Cl2 is etching of the growing surface, resulting in a rigid Si network.