Self-Diffusion in Silicon: Similarity between the Properties of Native Point Defects

Self-diffusion measurements in silicon are extended to the range 800–900 °C by monitoring ${}^{30}\mathrm{Si}$ diffusion in isotopically enriched structures. Comparing P, Sb, and self-diffusion under nonequilibrium conditions, we determine that the interstitial-mediated fraction of self-diffusion is confined between 0.50 and 0.62 in the temperature range of 800–1100 °C. This allows activation enthalpies of 4.68 and 4.86 eV to be determined for the interstitial and vacancy mechanisms, respectively. Both mechanisms are also found to exhibit large activation entropies. This result is in contrast to values extracted from metal diffusion experiments.