Fundamental role of ion bombardment for the synthesis of cubic boron nitride films

Abstract

Boron nitride film growth from B and N ion deposition is studied. We observe growth of the cubic phase $(c\ensuremath{-}\mathrm{BN})$ between 75 eV and 5 keV and a transition to ${\mathrm{sp}}^{2}$-bonded BN growth between 5 and 10 keV, as predicted by the cylindrical spike model. Atomic rearrangements in thermal spikes are identified as the mechanism responsible for $c\ensuremath{-}\mathrm{BN}$ formation and suppression of defect accumulation. The onset of defect accumulation eventually enhances the growth of ${\mathrm{sp}}^{2}$-bonded BN. The results highlight the fundamental role of the balance between thermal spikes and defect accumulation in ion deposition processes.