Silicon carbide thin films were synthesised by vapour phase epitaxy technique on silicon substrates using silane and propane as precursors. Methyltrichlorosilane (MTS) was added, and nitrogen was used as dopant precursor. Samples with different doping concentrations were obtained varying the nitrogen flow during the growth. Doping level for each sample was assessed using Raman technique, and a correlation between dopant flow and doping level was confirmed. The influence of MTS on nitrogen incorporation is analysed and discussed: the introduction of MTS increases the growth rate and increases the doping level. We exclude a direct doping effect by the MTS, but we think that it promotes the incorporation of nitrogen doping species. The crystalline quality of the as-grown films was evaluated using X-ray diffraction, assessing the good crystalline quality even in samples obtained using high growth rates and high doping level.