The evolution of defects versus thickness has been investigated in three different freestanding 3C-SiC samples, using TEM (Transmission Electron Microscopy) and LTPL (Low Temperature Photo-Luminescence) spectroscopy. In all samples, the stacking fault density reduces rapidly within the first 20 µm of the growth. Then it remains constant, at about 5x103 cm-1 up to the end. This behavior is attributed to the easy generation of stacking faults, even under a very low thermal stress, as in-situ experiments reveal. On the opposite the elimination of inversion domains, by bending boundaries during the growth, is found to be sample dependant. This is in good agreement with LTPL results.