Numerical simulation of the influence of electron injections on the short-term annealing in pulse-neutron-irradiated p-type Si

The physical reason behind the much more rapid short-term annealing progress in the presence of electrons in P-type silicon irradiated by pulse neutrons is investigated. Continuum equations coupled with defect reactions are used for the numerical simulation on the temporary evolutions of defects at different electron injection ratios. It is indicated that electron injections can significantly accelerate the creations of boron and carbon interstitials, but may have little influence on the creation of the vacancy-oxygen complex. The calculations on the relative concentrations of interstitials and vacancies in different charge states via the electron injection ratio show that more and more interstitials in the doubly positive charge state change into neutral ones, and neutral vacancies are always dominant with an increase in the electron concentration. The thermal diffusion coefficient of neutral interstitials is much larger than the ones of interstitials in other charge states. As a consequence, normal ionization enhanced diffusion for interstitials in the presence of electrons can significantly accelerate the short-term annealing progress in P-type silicon. Ionization enhanced diffusion coefficients for interstitials due to athermal diffusion are further estimated using the Bourgoin mechanism, and results indicate that the diffusion coefficients of positively charged interstitials are improved by several orders of magnitude when compared to their corresponding thermal diffusion coefficients. However, the production of boron and carbon interstitials is only accelerated by about one order of magnitude, which would be ascribed into such large thermal diffusion coefficients of neutral interstitials.