Investigation of BCN films deposited at various N₂/Ar flow ratios by DC reactive magnetron sputtering

In this paper, boron carbonitride films were deposited by a dc reactive unbalanced magnetron sputtering of conductive B₄C target in a mixture gas of nitrogen and argon. The films with various content of N were obtained by a varying N₂/Ar flow ratio in the mixed gas from 0/100 to 30/100. Structures and compositions of the films were investigated by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The results show that the content of B, C, N, and the ratio of each element binding states depend on the ratio of N₂/Ar flow. The nitrogen content showed the rising tendency and then came to the saturation stage with an increasing N₂/Ar flow ratio. The maximal N content of 33.1 at.% was obtained when N₂/Ar flow ratio was 30/100. Nitrogen in the film is prior to binding with B forming sp² B-N bond, and then with C forming sp² C-N bond, when the N₂/Ar ratio is over a certain value during the nitrogen was introduced into a vacuum chamber. The results of the FTIR indicate that the film is a compound of B-C-N atomic hybridization.