Analysis of extended defects in nitrogen annealed CZ silicon by optical and electron beam methods

The effect of annealing in nitrogen atmosphere on the formation of crystal defects in the OSF-ring of Czochralski silicon has been studied by comparison with samples annealed in oxygen atmosphere by using optical and electron beam based methods. By annealing in nitrogen the formation of extrinsic stacking faults is prevented whereas oxygen precipitates form in nearly the same density as in the oxygen annealed sample. Additionally, loop-like microdefects were generated that were not observed for annealing in oxygen ambient. The results are explained by assuming that extra vacancies are introduced into Si from the nitrogen annealing atmosphere. They are expected to recombine with Si interstitials, thus preventing the growth of the stacking faults, and to create the observed microdefects.