THE SYNTHESIS OF CUBIC BN FILMS USING A HOT CATHODE PLASMA DISCHARGE IN A PARALLEL MAGNETIC-FIELD

A method of synthesizing cubic boron nitride (c-BN) films by the activated reactive evaporation process was investigated. A special feature of the gas activation process is that a hot cathode plasma discharge in a parallel magnetic field is used. A conventional type of ion plating apparatus, with an electron beam gun for the evaporation of boron, was used to synthesize c-BN films on a single-crystal silicon plate. A stoichiometric boron nitride film was obtained by reacting boron vapour with high density nitrogen ions, prepared using a hot cathode plasma discharge in a parallel magnetic field around the substrate. Argon gas was mixed with the reactant nitrogen gas to enhance BN formation. An r.f. bias potential was applied to the substrate in order to obtain the cubic BN phase. The optimum value of the total gas pressure in the evaporation chamber was in the range 2.6 x 10(-2)-1.1 x 10(-1) Pa. The structures of the films obtained were characterized using IR absorption spectroscopy and X-ray diffraction analysis.