Synthesis of c-BN films by using a low-pressure inductively coupled BF3–He–N2–H2 plasma

Cubic boron nitride (c-BN) films were synthesized by low-pressure inductively coupled radio-frequency plasma (ICP) chemical vapor deposition (CVD) from a gas mixture of borontrifluoride (BF3), nitrogen, hydrogen and helium. BN films containing 50–80% cubic phase were obtained under 100 mTorr and at 750–1050 °C of substrate temperature. Substrate bias voltage required to obtain c-BN decreased down to − 20 V with increasing substrate temperature. The adhesion was also improved at high substrate temperatures as compared with those obtained in the B2H6–Ar–N2–H2 gas system, probably because of the decrease of bombarding energy and chemical effects of fluorine for selective deposition of c-BN.