The diffusion of D in diamond-like C films was studied. The D concentration profiles in D+-ion implanted films were measured by means of secondary-ion-mass spectrometry. A model was proposed, for describing the experimental depth profiles, in which it was assumed that atomic D was the diffusing species, whereas D in clusters was immobile. The results showed that the concentration of D clusters, relative to the total D concentration, increased when the total D concentration decreased; thus leading to concentration-dependent diffusion. The diffusion coefficients which were deduced for atomic D (figure 1) indicated an associated activation energy of 2.9eV. The solid solubility of D decreased with increasing temperature.

T.Ahlgren, E.Vainonen, J.Likonen, J.Keinonen: Physical Review B, 1998, 57[16], 9723-6