Synthesis and characterization of boron carbon nitride films by radio frequency magnetron sputtering

Boron carbon nitride (BCN) films were deposited on silicon substrates by ra dio frequency (r.f.) (13.56 MHz) magnetron sputtering from hexagonal boron nitride (h-BN) and graphite targets in an Ar-N-2 gas mixture of a constant pressure of 1.0 Pa. During deposition, the substrates were maintained at a temperature of 400 degrees C and negatively biased using a pulsed voltage w ith a frequency of 330 kHz. Different analysis techniques such as X-ray pho toelectron spectroscopy (XPS), Auger electron spectroscopy (AES), Fourier t ransform infrared spectroscopy (FLTIR), Raman spectroscopy, X-ray diffracti on (XRD) and scanning Auger electron microscopy (SAM) were used for charact erization. In addition, the mechanical and tribological properties of the f ilms were investigated by nano-indentation and micro-scratching. The carbon concentration in the films could be adjusted by the coverage area of a gra phite sheet on the h-BN target, and decreased with increasing bias voltage. It was found that the ternary compound films within the B-C-N composition triangle possessed a less ordered structure. B-N, B-C and C-N chemical bond s were established in the films, and no phase separation of graphite and h- BN occurred. At zero bias voltage, amorphous BC2N films with atomically smo oth surface could be obtained, and the microfriction coefficient was 0.11 u nder a normal load of 1000 mu N. Hardness as determined by nano-indentation was usually in the range of 10-30 GPa, whereas the Young's modulus was wit hin 100-200 GPa. (C) 2000 Elsevier Science S.A. All rights reserved.