Transition metals in amorphous samples exhibit a direct interstitial diffusion behavior which is retarded by temporary trapping at defects that are intrinsic to the amorphous structure. Diffusion was investigated here by means of Rutherford back-scattering spectrometry. The migration of Au tracer atoms was also studied by using neutron activation and sputter-sectioning analyses. It was found that the data (table 15) could be fitted by using foreign-atom interstitial diffusion coefficients for crystalline Si; modified by the presence of traps in concentrations of between 0.2 and 1at%, and with trapping enthalpies of about 0.9eV.

Determination of Diffusion Mechanisms in Amorphous Silicon. S.Coffa, J.M.Poate, D.C.Jacobson, W.Frank, W.Gustin: Physical Review B, 1992, 45[15], 8355-8

Table 15

Diffusivity of Au in Amorphous Si