The precipitation of Feo in n-type material, and the generation of Fe-acceptor pairs (controlled by the diffusion of Fe+ in p-type material), were investigated by using electron spin resonance methods. Isochronal annealing data showed that the temperature range within which Fe+ diffusion was active was lower than that for Feo. Annealing experiments which had been performed at various temperatures showed that the activation energies for the diffusion of Feo and Fe+ were equal to 0.80 and 0.68eV, respectively.

Charge-State-Dependent Activation Energy for Diffusion of Iron in Silicon. H.Takahashi, M.Suezawa, K.Sumino: Physical Review B, 1992, 46[3], 1882-5