OPTICAL-PROPERTIES OF CUBIC BORON-NITRIDE FILMS MADE BY A REACTIVE ION PLATING METHOD

Cubic boron nitride (c-BN) has been prepared using a magnetically enhanced plasma ion plating method. A magnetic field parallel to the electric field is used in conjunction with a hot cathode to produce a plasma at low pressure. R.f. power was simultaneously applied to the substrate holder to provide a negative bias for the desired ion bombardment. The optical properties of the c-BN films from the UV through the visible to near-IR were measured in comparison with hexagonal BN, mixed-phase BN and amorphous BN prepared in the same apparatus under different conditions, using a double-monochromator spectrophotometer. The crystal structures of these films were identified by electron diffraction analysis. It was found that c-BN films deposited on quartz substrates have the highest optical transparency, as well as the shortest wavelength above which they are transparent.