For the realization of good quality 3C-SiC films epitaxially grown on Si, the perfection of the film during the early stage of growth is substantial. In this paper, the beneficial role of flash lamp annealing (FLA) for the elimination of the defects in the SiC films and the strain reduction at the SiC/Si interface is discussed. FLA is a highly transient process having a flash duration of a few milliseconds. When the energy density is sufficiently high, it melts the silicon at the SiC/Si interface increasing the temperature there well above the melting point of silicon. The melted Si dissolves the 3C-SiC near the interface. Additionally, the uppermost part of the 3C-SiC film is annealed due to the heat dissipation during the (lash duration and the solidification of the molten region. During the solidification of the C-rich Si melt, SiC grows by liquid phase epitaxy at the annealed uppermost 3C-SiC film which acts as a seed. This process results in a substantial improvement of the SiC film eliminating also the cavities and the stress at the interface.