Thick and adherent cubic boron nitride films grown on diamond interlayers by fluorine-assisted chemical vapor deposition

Using plasma-enhanced chemical vapor deposition (PECVD) based on fluorine chemistry, the limitations hindering the practical use of cubic boron nitride (cBN) films in mechanical applications have been overcome. The CVD method presented is characteristic with (a) the direct cBN growth on diamond without soft, noncubic BN interface layers, (b) the synthesis of cBN films with extraordinary adhesion to the substrates and high mechanical properties, and (c) the scalable process providing thick, large-area cBN films at high deposition rate even on rough and untreated surfaces. These prime technological properties open the route to the mechanical exploitation of cBN films, particularly in tribological and tool applications. The reduction of the bias voltage in the PECVD process presented to a value of -20 V not only provides high-quality films, but also gives physical insight into the cBN growth mechanism. (C) 2004 American Institute of Physics.