Influence of raw gases on B-C-N films prepared by electron beam excited plasma CVD

摘要

B-C-N films were deposited with electron beam excited plasma-chemical vapor deposition focusing on the structural stability where their compositions lie in the vicinity of BN. Film composition was controlled by varying process gas flow rates and was x = 1.08-1.18 and y=0.01-0.34 for B_xC_yN. The dependence of Fourier transform infrared transmission spectra and hardness on composition show that the structure is very sensitive to film carbon content: a cubic phase is found only in a carbon-poor region and disappears abruptly when carbon content is increased. Results of X-ray diffraction and X-ray photoelectron spectroscopy measurement suggest that films involving a cubic phase of carbon-poor B-C-N compound were obtained. The disadvantage in forming a cubic B-C-N phase in a low carbon region is understood in terms of bonding energy and local charge neutrality, while the entropy of mixing should enable very low carbon solubility.