The stability of several states of N was investigated by means of first-principles calculations. A single N at a split interstitial site and bond center site was more stable than that at a tetrahedral or hexagonal site. The N pair was more stable, than a single N at the split interstitial site, by 4.3eV. This indicated that the N pair existed even near to the melting point of Si. The binding energy between the N pair and 2 vacancies indicated that a complex which consisted of the N pair and 2 vacancies could exist at the temperature of void aggregation. The formation of the complex could affect the concentration or diffusivity of the vacancy.

First-Principles Calculation of the Interaction between Nitrogen Atoms and Vacancies in Silicon. H.Sawada, K.Kawakami: Physical Review B, 2000, 62[3], 1851-8