After a short review of the present stage of knowledge of the Si[100] and β-SiC surface reconstructions and Si carbonisation mechanism, we discuss the possible origin for the change in sign of the interfacial strain recently observed in this strongly mismatched cubic hetero-epitaxial system as a function of the initial carbonisation temperature. Both the interfacial and anisotropic character of this strain are confirmed by micro-Raman analysis of cleaved CVD-grown samples, which reveal also how extended defects relieve the residual strain after the growth of a few micrometers of 3C-SiC. Such pseudo-substrates have been used as a cubic template for the MBE growth of cubic nitrides and Raman scattering results on β-AlN materials and cubic GaN/AlN stacked quantum boxes are presented. Finally, the potential andlimitations of such 3C-SiC pseudo-substrates for nitride growth are discussed.