MANUFACTURE OF C-BN FILMS WITH IMPROVED ADHESION

The authors have succeeded in making a c-BN film with stoichiometric composition through the use of a hot cathode plasma discharged within a parallel magnetic field. The c-BN film prepared by this method, however, did not demonstrate good adhesion because of the internal stress within the film. Accordingly, several kinds of countermeasures for this problem have been attempted to improve the adhesion to the substrate. These were: (1) to deposit the film using a gradient-controlled component layer technique; (2) to provide a titanium interlayer between the substrate and the film made according to (1); (3) to heat treat the film made according to (1) and finally (4) to heat treat the film made according to (2). The adhesion was measured for each countermeasure using a scratch tester. The effect of these countermeasures on the adhesion and the internal stress of the c-BN film is discussed.