We discuss the possible source of surface instabilities (with specific reference to the step bunching phenomena) during the growth of cubic and hexagonal Silicon Carbide polytypes. For this analysis we use: results from super-lattice Kinetic Monte Carlo simulations, atomic force microscope surface analysis and literature data. We show that only hexagonal polytypes with misorientation cut toward the <11-20> direction suffer “intrinsically” the step bunching phenomena (i.e. it are present, independently on the growth conditions) whereas cubic polytypes and hexagonal ones with misorientation cut toward the <10-10> direction do not.