Chemical vapor deposition of Si in a lamp-heated single-wafer reactor is studied by monitoring the growth rate of films deposited on bare S. silicon-on-insulator (SOI), and oxidized Si wafers. The growth rate is consistently higher for deposition of polycrystalline Si than for epitaxy of Si. due to different kinetics dictating the two depositions. Epitaxy of Si on SOI shows a higher overall growth rate than on hare Si. Likewise, deposition of polycrystalline Si on oxidized Si wafer with a 4000 Angstrom thick oxide has a higher growth rate than on that with 15 Angstrom oxide. These are attributed to surface emissivity variation during Si deposition. The difference in kinetics plays a more dominant role than the surface emissivity variation in affecting the growth rate for the depositions studied.