The microstructure of the annealed by flash lamp process 35nm thick 3C-SiC films epitaxially grown on Si, is studied by transmission electron microscopy. The flash lamp annealing aparatus consists of Xe lamps powered by discharging capacitors producing pulses of 20 ins. The partial dissolution of the SiC film into Si substrate and subsequent recrystallization of the film improves the quality of the films.