In a polemic discussion, Ural et al. recalled that they had presented results on the self-interstitial and vacancy contributions to self-diffusion by comparing P, Sb and Si diffusion experiments which had been performed under equilibrium and non-equilibrium conditions at between 800 and 1100C. They had deduced activation enthalpies of 4.68 and 4.86eV for the self-interstitial and vacancy-mediated mechanisms of self-diffusion, respectively. These contrasted with the corresponding results which had been deduced from metal diffusion experiments. They declared that, in interpreting metal diffusion, certain assumptions were involved. Their experimental approach, involving isotopically enriched Si structures, instead yielded the self-interstitial component of self-diffusion directly. However, Bracht et al. argued that the interpretation of the above experiments was overstated and misleading because metal diffusion experiments existed whose analysis did not include any assumptions that could not be explicitly verified. In addition, an objective representation of their self-interstitial contribution to self-diffusion exhibited no significant deviation from the corresponding results which had been deduced from metal diffusion.

Comment on Self-Diffusion in Silicon: Similarity between the Properties of Native Point Defects. H.Bracht, E.E.Haller, A.Ural, P.B.Griffin, J.D.Plummer: Physical Review Letters, 2000, 85[22], 4835-6