Cubic silicon carbide (3C-SiC) is an emerging material for high power and new generation devices, but the development of high quality 3C-SiC layer still represents a scientific and technological challenge especially when grown on a Si substrate. In the present lecture, we discuss the use of a buffer layer between the epitaxial layer and the substrate in order to reduce the defectiveness and improve the overall quality of the SiC epi-film. In particular, we find that the morphology and the quality of the epi-film depends on the carbonization temperature and the concentration of Ge in close proximity of the Si1-xGex/SiC interface. Ge segregation at the interface influences the film quality, and in particular a [Ge] > 12% in close proximity to the interface leads to the formation of poly-crystals, while close to 10% induces a mirror like morphology. Moreover, by finely tuning the Ge concentration and carbonization temperature, crystal quality higher than that observed for SiC grown on bare silicon is achieved.