The physicochemical properties of SiC-based deposits, obtained from the thermal decomposition of CH3SiCl3(MTS) in hydrogen, under conditions of reduced pressure (P < 20 kPa) and low temperature (T < 1400 K), are studied. The morphology, the structure, the nanostructure and the chemical composition of the deposits are discussed from a kinetic and a thermodynamic point of view. They are closely related to the kinetic control regime (either mass transfer or chemical reactions). The silicon excess has a pronounced influence on the morphology and the nanostructure of the deposits.