Characterization of cubic boron nitride growth using UV-extended real-time spectroscopic ellipsometry: Effect of plasma additions and dynamic substrate bias steps

Ultraviolet-extended real-time spectroscopic ellipsometry (UV-RTSE) was applied to characterize the growth and layered structure of BN films deposited on c-Si substrates using pulsed dc sputtering of a B₄C target with rf substrate biasing. Focus was on the effects of the rf substrate bias on the phase evolution of BN films with high cBN content deposited under static conditions. It was possible to identify the substrate bias magnitude below which cBN growth reverts to hBN+cBN mixed-phased growth gain, and that below which hBN+cBN growth reverts to hBN. The effects of small plasma additions including H₂ and O₂ on the film evolution under these dynamic deposition conditions were also determined.