The growth kinetics of silicon carbide (SiC) by chemical vapor deposition (CVD) from methyltrichlorosilane (MTS:CH3 SiCl3) was investigated by in situ measurements of growth rates, which were converted from the deposited weight by thermogravimetry, as a function of temperature and partial pressure of MTS (P-MTS). The growth rates were limited by surface reactions at lower temperatures and by vapor mass transfer at higher temperatures. The limiting kinetic processes changed at a critical temperature of about 1300 degrees C independent of P-MTS variation. Although these results are supported by the stagnant gas layer model, it is impossible to explain the P-MTS dependence of the activation energy by this model. The calculated growth rates from the two-sites competitive adsorption model under equilibrium partial pressures fit the experimental growth rates as a function of P-MTS. The heat of adsorptions was 32.3 kcal/mol for SiCl3 and 26.8 kcal/mol for CH3. Considering the adsorption coverage of CH3 on Si sites and SiCl3 on C sites, it was concluded that the growth rates of SiC were controlled by the amount of CH3 adsorbed on Si sites.