Model for bulk effects on Si interstitial diffusivity in silicon

Literature values for the diffusivity of the silicon interstitial or interstitialcy, I, range over several orders of magnitude and have activation energies between 1 and 4 eV. We propose a model for bulk trapping effects on the I diffusivity which provides a consistent explanation for the observed discrepancies. It reconciles the effects of different materials (float-zone, Czochralski, and epitaxial silicon) and processes (diffusion and gettering) on the apparent value of the I diffusivity. New experimental results which directly indicate substantial bulk effects in different types of silicon support the validity of the model.