Characterization of Buffer Layers for Sic CVD

Abstract: Silicon Carbide has been grown by rapid thermal carbonization of (1 00) and (1 1 1) Si surfaces at atmospheric pressure using 1 lpm hydrogen (H2) as a carrier gas and propane (C3H8) with concentrations ranging from 0.025-1 3%. RHEED investigations have shown single crystal-line 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 (1 11). Above 0.6 % a carbon rich poly-crystalline layer covering completely the surface was formed. The carbon has both graphitic and carbidic nature. The graphitic content could be decreased by post deposition H2 annealing without changing the polycrystalline nature of this top layer. Best crystallinity were found at 1250 OC, 0.15 % propane and 30-90 s. 1