Phase separation in magnetron sputtered superhard BCN thin films

摘要

The similar crystalline structure of diamond and cubic boron nitride suggests the synthesis ofsuperhard thin films containing boron, carbon and nitrogen. BCN thin films have been prepared byreactive r.f.-magnetron sputtering of a hexagonal boron nitride target in an argon/acetyleneatmosphere of a constant pressure of 2×10{sup}-2 mbar. A deposition temperature of 600 ℃leads to nearly hydrogen-free BCN films. At a flow ratio of 0.05% C{sub}2H{sub}2/Ar, thecomposition of the deposited BCN films is close to B{sub}5CN{sub}3 as a result of energy dispersiveX-ray (EDX) and elastic recoil detection (ERD) measurements. By applying a r.f.-substrate bias, theion energy has been varied at a constant ratio of ions to film-forming particles of 4. The BCN filmsshow a maximum in stress at an ion energy of 110 eV due to knock-on subplantation of argon ions anda phase separation into carbon, boron and cubic boron nitride regions as a result of X-ray diffractioninvestigations, Auger electron- and infra-red spectroscopy.