Characterisation of crystallinity of SiC-surface layers produced by ion implantation

Carbon implantations into silicon were carried out in order to form thin surface layers of SiC. Single crystalline <100> silicon samples were implanted with 40 keV 13C ions with a fluence of 3.8x1017 ions/cm2 and subsequently thermally treated under high vacuum conditions at different temperatures using a 20 keV electron beam. The isotope 13C offers the advantage to measure the carbon redistribution caused by the thermal treatment process with the nuclear resonance reaction analysis. The crystallinity of the 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 shows obviously that the 6H-SiC phase coexists with the 3C-SiC modification in SiC layer.