Epitaxial growth of α-SiC layers by chemical vapor deposition technique

Abstract

Single crystals of α-SiC were grown on α-SiC substrates at a temperature between 1570 and 1630°C with the standard gas flow rate: H 2 ∼ 1 liter/min, SiCl 4 ∼ 1.7 ml/min and C 3H 8 ∼ 0.1 ml/min. The grown layers were transparent greenish-blue, and surfaces were mirror-like. By an X-ray back-reflection Laue pattern and a reflection electron diffraction method, the grown layer was identified as 6H-SiC, one polytype of α-SiC. Crystal growth was influenced by substrate temperature, flow rates of reaction gases and the surface polarity of the substrate. The growth rate decreased with increase of the substrate temperature in the above temperature region. A lamellar structure was observed on the (0001) Si surface and a mosaic structure was observed on the (000 1 )C surface. The mole ratios of both SiCl 4 and C 3H 8 to H 2 and that of Si to C had some influence on crystal growth. Undoped layers were n-type due to nitrogen. P-type SiC was grown by doping Al during crystal growth. Doping effects were studied by photoluminescence and electrical measurements.