Raman characterization of boron doped tetrahedral amorphous carbon films

Boron doped tetrahedral amorphous carbon films, having boron content from 0.59 to 6.04 at.%, have been prepared by a filtered cathodic vacuum arc system using boron mixed graphite targets. The influence of boron on the surface morphologies and microstructures of the films was studied by atomic force microscopy and Raman spectroscopy. The surface images showed that the irregular tops on the surface of the films tended to form larger clusters as boron content increased. The Raman spectra of the films were, respectively, deconvoluted using Gaussian and Breit-Wigner-Fano line shapes. The Raman parameters, including the intensity ratios, peak positions, peak widths and coupling coefficients, obtained from both line shapes were described and compared. It was found that both line shapes could produce consistent results except the peak widths of G bands. The major effect of boron introduction was to increase the clustering of the sp² phase in the films.