Exploration of Growth Window for Phase-Pure Cubic Boron Nitride Films Prepared in a Pure N2 Plasma

Cubic boron nitride (c-BN) films were prepared via radio frequency (RF) magnetron sputtering from a hexagonal boron nitride (h-BN) target in a pure N2 plasma. The composition and microstructure morphology of the BN films with different deposition times under pure N2 plasma or mixed Ar/N2 plasma were investigated with respect to the nucleation and growth processes. The pure-phase c-BN growth window was obtained using pure N2 gas. The effects of pure N2 gas on the growth mechanism, structural morphology, and internal compressive stress of the as-synthesized c-BN films were studied. Using pure N2 gas instead of additional Ar resulted in improved microstructure quality and much reduced compressive stress, suggesting a fundamental strategy for achieving high-quality c-BN films