Kinetics approach to the growth of cubic boron nitride

We have deposited cubic BN films on silicon (100) using a novel ion-assisted RF-sputtering process. Our efforts over the past several years have enabled us to significantly reduce the ion-energy needed to form the cubic phase, with values now substantially less than 100 eV. Through a better understanding of the growth process we have been able to make improvements in film crystallinity and orientation, with an associated reduction of the high film stress which has severely limited film thickness in the past. The combination of low-energy nitrogen ions and high temperature growth has enabled us to deposit cubic BN films as thick as 1.9 mu m. A nucleation study, performed using scanning force microscopy, shows that the cubic BN is nucleating as triangular crystallites, indicative of (111) growth. More specifically, the cubic BN appears to be nucleating on the edges of perpendicularly oriented hexagonal planes such that the cubic BN [111] is normal to the hexagonal BN [0002] (c-axis). The results suggest a pathway to ''compliant'' oriented growth on a variety of substrates.