Growth rates from 10 to 38 μm/h of single crystal 3C-SiC on planar Si (001) substrates have been obtained in a low-pressure horizontal hot-wall CVD reactor. The propane-silanehydrogen gas chemistry system with HCl added as a growth additive, which allows an increased amount of silane to be introduced into the reactor during growth, was used. The 3C-SiC film growth rate versus silane mole fraction was found to be a linear function in the range from 0.43x10-3 to 1.50x10-3. Nomarski optical microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy and X-ray diffraction were used to characterize the deposited layers. The X-ray rocking curve taken on the (002) diffraction plane of a 12 μm thick 3CSiC (001) layer displayed a FWHM of 360 arcsec, which indicates the films are mono-crystalline.