Sequential ion-induced stress relaxation and growth: A way to prepare stress-relieved thick films of cubic boron nitride

Abstract

It is shown that the bombardment of high quality cubic (c-) BN films with 300 keV Ar+ ions leads to a strong relaxation of their compressive stresses without destroying the cubic phase if the total ion fluence is kept below an upper limit. In addition, it was found that on top of such a stress-relieved film a further pure c-BN layer can be grown, but it builds up compressive stress again. Based on both results, a procedure is developed to grow thick (>1 μm) c-BN films (>80% c-BN) exhibiting low residual stress and long term stability under ambient conditions.