Silicon carbide films were deposited on Si(100) wafers in the temperature range 950-1150°C, from a mixture of Si(CH3)4 + H2 in a hot-wall low-pressure chemical vapor deposition (LPCVD) reactor. A thin a-SiO2 layer of 60 Å was grown on the Si substrate prior to deposition. The total pressure, H2 flow rate and H2 Si(Ch3)4 ratio were fixed at 0.65 Torr, 1300 cm3/min and 130, respectively. The microstructure of the as-grown films was investigated by X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and electron microprobe analysis (EPMA). The deposition reaction of SiC is thermally activated with an apparent activation energy of 150 kJ/mol. It was found that a mixture of micro-crystalline and amorphous phases is formed with an overall C content of 60 at% at the deposition temperature of 950°C. Crystallinity is improved and microstructure becomes columnar as growth proceeds on films deposited at 1000°C. Films grown at temperatures between 1050 and 1105°C are stoichiometric β-SiC polycrystals, with a columnar morphology and well developed (111) preferential orientation. In agreement with a columnar grains development, surface roughness increases dramatically as deposition temperature changes from 950 to 1150°C. At T = 1105°C cylindrical crystallites with diameters ∼ 150 nm are observed in films ∼ 20 μm thickness. Planar defects perpendicular to the axis of the crystallites are microtwins generated by the rapid incorporation of a high number of atoms with low adatom mobilities and are responsible for the fast growth along the  direction. © 1995.