Characterization and comparison of hydrogenated and unhydrogenated amorphous boron carbon nitride films deposited via radio frequency magnetron sputtering

Abstract

We have prepared amorphous boron carbon nitride (BCN) and hydrogenated amorphous BCN (BCN:H) films via radio frequency magnetron sputtering without and with H₂ and investigated the effects of hydrogen on the properties of the BCN and BCN:H films. The carbon content of the BCN:H films increased slightly with increasing H₂ flow ratio. Raman measurements clarified that the hydrogen dilution prevented the formation of sp² carbon clusters. The Fourier transform infrared absorption peaks corresponding to CH_n stretching vibration modes increased gradually with the hydrogen flow ratio. The optical bandgap and electrical resistivity of the BCN:H films were larger than those of the BCN films. Additionally, the optical bandgap and electrical resistivity of the BCN:H films increased as the H₂ flow ratio increased, probably due to a decrease in sp² CC bonding caused by the introduction of hydrogen during deposition, as shown by X-ray photoelectron spectroscopy. It was found that the BCN:H film exhibited a higher resistivity than the BCN film under almost the same optical bandgap. This result suggests that introducing hydrogen reduces defect density in the BCN:H film. The critical load decreased with the H₂ flow ratio owing to increased internal stress. The tribological properties of the BCN:H films were improved with the H₂ flow ratio. The root-mean-square roughness of the films, as estimated from atomic force microscope images, decreased with an increase in the hydrogen flow ratio.