To assess deformation issues in the vapor phase epitaxy of 3C-SiC on (0 0 1) and (1 1 1) Si substrates, we investigated different pre-growth (carburisation) procedures, adding various amount of SiH4 to C3H8. The mechanical deformation of the samples was measured by quantitative Makyoh topography, through which 3D deformation maps of the entire wafers were obtained. X-ray diffraction was used to check the crystal quality of the layers and, in transmission geometry, to assess whether the observed deformation was plastic or elastic. Residual stress of the deposited 3C-SiC layers was investigated across the entire wafer substrates by using Raman spectroscopy and values between 0.5 and 1 GPa were found. It was observed that, for a given carburisation procedure, the crystalline orientation of the Si substrates plays an important role in the substrate curvature (convex and concave). The addition of SiH4 during carburisation ramp leads to increased deformation for SiC/Si (0 0 1), while decreased deformation for SiC/Si (1 1 1).