We investigated various chemical systems for the CVD step in the CF-PVT bulk crystal growth method, in order to improve the feeding of the SiC polycrystalline source. In this paper, we present experimental results focusing on the comparison of CVD deposition rate and crystal growth rate versus chemical system and experimental parameters. We show the validation of the PVT step under an hydrogen atmosphere or an atmosphere containing chlorinated species. CF-PVT growth rates up to 150 mum/h are demonstrated. Results are discussed on the basis of thermodynamic calculations and numerical simulations of the temperature distribution in the crucible.