Controlling the nucleation environment of c-BN films and their related properties

Cubic boron nitride (c-BN) films were deposited using radio-frequency ~rf! magnetron sputtering. A type of turbostratic boron nitride (t-BN) growth was found by reducing the substrate bias during deposition. Transmission electron microscopy ~TEM! study showed that the t-BN served as a different nucleation environment for c-BN compared to those reported in the literature by many other groups. The nucleation environment corresponded to a lower film internal stress level and thus facilitated the production of thicker c-BN films. The fraction of different t-BN/c-BN environments could be controlled and altered by varying the deposition conditions. The films containing different t-BN/c-BN environments were compared in phase concentration, stoichiometry, microstructure, and internal stress level. Additional insight was added to the film growth mechanism.