Raman scattering from hydrogenated amorphous carbon films

Abstract

Amorphous hydrogenated carbon films (a-C:H), as-deposited and modified by rapid thermal annealing, by implantation, and by laser irradiation were studied by Raman scattering. The ratio of carbon to hydrogen in each of the samples was determined by Rutherford backscattering (RBS) and proton recoil spectra. The hydrogen content was found to decrease with increasing annealing temperatures, with ion implantation, and with laser irradiation. The Raman spectra were analyzed to obtain peak position and linewidth of the D and G lines of the disordered graphite and the intensity ratio (ID/IG) of these lines correlated with the C/H ratio obtained from RBS and proton recoil spectra. These measurements indicate that with increasing annealing temperature, with ion implantation, and with the laser radiation, the a-C:H films are modified from less tetrahedrally bonded to more trigonally bonded; the a-C:H films become more graphitic.