Dose-rate influence on the defect production in mev proton-implanted float-zone and epitaxial n-type silicon

The production of stable vacancy-related point defects in proton-implanted float-zone and epitaxial silicon has been studied in the low dose range (<= 1E10/cm2) as a function of dose-rate. The well-known “inverse dose-rate” effect has been observed in both types of materials with a decrease in the concentration of vacancy-related defects as the dose-rate increases. The effect is less pronounced in oxygen lean epitaxial silicon. Moreover, a continuous decrease of the vacancy-related defect concentration as a function of the flux was measured while a threshold was expected according to previous studies. Both of these results can be explained by a simple calculation, taking into account the influence of the oxygen concentration as well as the influence of the diffusion coefficient of point defects on the “inverse dose-rate” effect.