The chemical vapor deposition of silicon from disilane under reduced pressure in an impinging jet reactor has been studied experimentally and simulated numerically by a 2D model. The measured deposition rate and profile have been compared to the results of the calculations performed with various hypotheses concerning both gas-phase and surface reactions. The influence of the number of species considered, of the kinetic rate constants, and of the models used for the reactive sticking coefficient of silane and disilane were investigated. Among the 17 species that may be present in the gas phase, a mechanism including 8 silicon-carrier species has been determined to represent satisfactorily the deposition rate and profile experimentally observed.