The diffusion of C, and of 5 other elements, in amorphous C films was studied. One set of samples were sp2-dominated amorphous C and the other set of samples were sp3-dominated tetrahedral amorphous C. The films were deposited by using mass-separated ion beam deposition under ultra-high vacuum conditions. The diffusion of 13C, as well as of H and D, was studied by using high-resolution elastic recoil detection analysis. No apparent self-diffusion could be detected. The H diffusion was found to begin at between 600 and 800C. Activation energies of 3.34 and 3.39eV were found for D diffusion in tetrahedral amorphous C and amorphous C, respectively. The diffusion of metals in tetrahedral amorphous C was studied by using W, Cu and Ag. No diffusion took place at annealing temperatures of up to 1000C. During annealing at 1200C, the tetrahedral amorphous C was converted into graphite; thus making diffusion into the C matrix possible. The fact that there was no diffusion of Cu in tetrahedral amorphous C at below 1200C showed that tetrahedral amorphous C could be a possible diffusion barrier between Cu and Si.

Diffusion in Diamond-Like Carbon. H.Kröger, C.Ronning, H.Hofsäss, P.Neumaier, A.Bergmaier, L.Görgens, G.Dollinger: Diamond and Related Materials, 2003, 12[10-11], 2042-50