Cubic boron nitride film residual compressive stress relaxation by post annealing

The authors demonstrate that the residual compressive stress in cubic boron nitride films could be relaxed by 1500 K post annealing in H2 atmosphere. According to the IR peak shifting, approximately 4.5 GPa stress was relaxed after 4 hours annealing. Thus film adhesion was improved significantly, cubic boron nitride films with a cubic phase concentration of 90% (vol%) and a thickness of more than 200 nm showed excellent stability and no delaminations were observed even after annealing for over 30 months in the open air, while films without annealing delaminated from substrates within 1 week. Moreover, the relaxation of the compressive stress is accompanied with cubic boron nitride d (111) interplanar distance broadening and corresponding IR peak intensities increasing.

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► High-quality cBN films were deposited on Si and quartz substrates.
► The intrinsic stress was relaxed by 1500 K annealing without destroying film structure
► cBN films have not delaminated for more than 30 months
► Stress relaxation is accompanied with IR peak intensities increasing.