A thermodynamic study has been done to understand the impact of the temperature, the pressure and the composition of the gas mixture during SiC pre-growth etching. It is shown that H-2 etching can lead to the formation of a solid silicon phase. Varying the temperature, the formation of this Si phase can be avoided. The influence of added C3H8 to H-2 has also been investigated. It is found that the formation of Si droplets can be eliminated. To complete the study, experiments have been performed in a horizontal CVD reactor. The results are in good agreement with the thermodynamic approach. Etch rates have been deduced from infra-red reflectivity measurements.