Hydrogen tracer diffusion was studied in amorphous SiC films which had been produced by radio-frequency magnetron reactive sputtering and which contained about 0.5at%H. The diffusion experiments were carried out between 700 and 1000C, with ion-implanted D tracer isotopes and secondary ion mass spectrometry. Effective diffusivities were deduced which obeyed Arrhenius behaviours with activation energies of 3.0 to 3.4eV and pre-exponential factors of the order of 10-4 to 10-5m2/s. These results could be explained by a trap-limited diffusion mechanism for H, where the tracer atoms were temporarily trapped by C dangling bonds, which had approximately the same binding energy to H.

Comparative Study of Trap-Limited Hydrogen Diffusion in Amorphous SiC, Si0.66C0.33N1.33, and SiN1.33 Films. H.Schmidt, G.Borchardt, U.Geckle, M.Bruns, H.Baumann: Journal of Physics - Condensed Matter, 2006, 18, 5363-70