X-ray double crystal and X-ray topographic characterization of silicon carbide thin films on silicon, titanium carbide, 6H-silicon carbide, and aluminum nitride/sapphire substrates

Abstract

The structure, strain and defects in epitaxial silicon carbide (SiC) thin films on aluminum nitride/sapphire ( AlN Al 2O 3 ), silicon (Si), titanium carbide (TiC) and 6H-SiC substrates were analyzed by X-ray diffraction, X-ray double crystal diffractometry and X-ray topographic techniques. The SiC thin films were confirmed to be epitaxials with a zinc blende structure when grown on Si, TiC and vicinal 6H-SiC, and a wurtzite 6H polytype structure when grown on AlN Ai 2O 3 . The dislocation densities in the SiC films are in the order of 10 8 to 10 11 and are comparable. The experimental stress agrees well with the theoretical one calculated from the thermal expansion coefficient mismatch between the film and the substrate. X-ray rocking curves and X-ray topographs suggest that considerable amount of defects were generated in the Si substrates during the thin film growth process whereas the sapphire substrates remain defect free.