Carbon implantations into silicon were carried out in order to form thin surface layers of SiC. Single crystalline h100i silicon samples were implanted with 40 keV 13 C ions with a fluence of 3.8 Â 10 17 ions/cm 2 and subsequently thermally treated under high vacuum conditions at different temperatures using a 20 keV electron beam. The isotope 13 C offers the advantage to measure the carbon redistribution caused by the thermal treatment process with the nuclear resonance reaction analysis. The crystallinity of SiC surface layers is studied by X-ray diffraction and transmission electron microscopy measurements. A polycrystalline 3C-SiC surface layer with a low content of 6H-SiC grains is formed with a thickness of about 70 nm. The analysis of high resolution TEM micrographs from the interface region obviously shows that the 6H-SiC phase coexists with the 3C-SiC modification in the SiC layer.