UNIFORM DEPOSITION OF DIAMOND FILMS USING A FLAT FLAME STABILIZED IN THE STAGNATION-POINT FLOW

For uniform deposition of diamond films by acetylene/oxygen combustion flames, the flat flame stabilized in the stagnation-point flow in front of the substrate has been realized by adding hydrogen to reduce the burning velocity. The flat flame stability was examined for the hydrogen/acetylene/oxygen ratio and the flow velocity of the reactant gas. In the flat flame, fields of temperature and concentrations of radical species which take part in diamond deposition, are homogeneous on the surface of the substrate. It has been confirmed by scanning electron microscopy and Raman spectroscopy that diamond film deposited by the round flat flame with a diameter of about 7 mm, are uniform over area with nearly the same diameter of the flame.