CHARACTERIZATION OF BUFFER LAYERS FOR SIC CVD

Silicon Carbide has been grown by rapid thermal carbonization of (100) and (111) Si surfaces at atmospheric pressure using 1 lpm hydrogen (H-2) as a carrier gas and propane (C3H8) with concentrations ranging from 0.025-1,5%. RHEED investigations have shown single crystalline SiC as well as additional phases depending on the propane concentration. A set of kinetic phase diagrams were determined. The chemical nature was examined by AES. At concentrations below 0,1% additional silicon and an increasing number of defects were found. The growth on (100) substrates has shown a change in orientation toward (111). Above 0.6% a carbon rich polycrystalline layer covering completely the surface was formed. The carbon has both graphitic and carbidic nature. The graphitic content could be decreased by post deposition H-2 annealing without changing the polycrystalline nature of this top layer. Best crystallinity were found at 1250 degrees C, 0.15% propane and 30-90 s.