Formation of cubic boron nitride films by arc-like plasma-enhanced ion plating method

Abstract

Thin cubic boron nitride (cBN) films were synthesized at 350 °C on various substrates such as silicon, stainless steel, TiN-coated WC–Co and WC–Co by means of an arc-like plasma-enhanced ion plating process. In this process, polycrystalline cBN films were obtained at deposition rates of 0.004 to 0.03 μm/min. The infrared spectra showed strong absorption at 1050 cm−1, indicating cubic structure of the deposited film. The electron diffraction patterns also showed the cubic structure, with a lattice parameter of 3.63 Å. It is inferred that ion bombardment during film growth plays a important role in the formation of cBN films. The cBN films deposited in this process had a high compressive stress of 4×1010dyn/cm2, which is significantly greater than the value of hard amorphous boron nitride (iBN) films, 1.6×1010dyn/cm2. The internal stress of cBN films was greatly reduced if iBN was used as a buffer layer between cBN and substrate.