Characterization of new ultra-hardness material-carbon nitride and rhombohedral boron nitride syntesized using electron cycrotron resonance plasma

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In this study. carbon nitride films and boron nitride films werr produced and characteized to investigate new function of these films. Raman scattering analysis reveals that the amorphous carbon nitride films deposited using an electron cycrotron resonancc (ECR) plasma enhanced chemical vapor deposition (CVD) apparatus had dianond-like carbon (DLC) structure as a fundamental structure. The relative nitrogen fraction [N] / ([N]+[C]) of the resulting films were 0.08 as a macimum value at every experimental conditions. IR spectra analysis reveals that nitrtogen atoms were substituted for carbon atoms or terminated carbon dangling bonds. Nitrogen containing carbon films deposited using an ion beam sputtering method or a magnetron sputtering method had DLC structure as the fundamental structure. The relative nitrogen fraction [N] / ([N] + [C]) of the resulting films were restricted to valus of 0.08. These results strongly suggest that the nirogen composition in the resulting films were rest … More ricted with fundamental structure of the felms and independent upon synthetic process. Theoretical composition of nirtogen calculated using the random covalent network theory was good agreement with experimental resuits. Therefore nitrogen composition in nitrogen-containing carbon films were found to be restricted to structrual factor.An indentation creep test has been performed to investigate the namo-structure changing of nitrogen-containing carbon films. It was found that viscous flow of the nitrogen-containing carbon films were promoted as compared with the films without nitrogen. Furthermore the critical force of the viscous flow beginning was decreased with the presence of the -C=N bond. This nano-indentation creep technique was found to be the effective technique in evaluation of nano-structure changing of the films.We have also produced boron nitride films using an r.f.plasma CVD method from BCl_3 and N_2 gas. Resulting films were found to be boron-rich composition. B-N bonds were found to form sp^2 bond from IR spectra. Hardness of the resulting films determined by an ultralow-load micro-hardness indenter were about 20GPa. The strain rate sensitivity exponent (m-value) detemined by an indentation creep test was 0.005-0.008. This value was found to be similar to DLC or glass. Less