Influence of ionic bombardment on cubic boron nitride (c-BN) thin film deposition by r. f. magnetron sputtering

Abstract

Thin films of cubic Boron Nitride (c-BN) were deposited by d. c. and r. f. (13,56 MHz) multi-target magnetron sputtering from high-purity (99,99 %) hexagonal boron nitride (h-BN) target, in an Ar (95%)-N2 (5%) gas mixture. Films were deposited at 300 and 900 oC, with power density of 7 and 24 W/cm2. In order to obtain the highest fraction of the c-BN phase, a d. c. substrate bias voltage between 0 and -250 V, as well as an r. f. substrate bias voltage between 0 V and 350 V were applied during the film growth. Characterization of the microstructure, composition, morphology, topography and thickness of the films was carried out by Fourier Transformed Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atom Force Microscopy (AFM). It was found that BN films deposited at 300 oC, at a pressure of 4 x 10-3 mbar and under -150 V of r. f. bias, applied for 35 min, presented the highest c-BN fraction, close to 85%.

Keywords

• magnetron sputtering
• cubic boron nitride
• ion bombardment