Energetics of Various Electrically Deactivating Defects in Heavily n-type Si.

Based on first-principles pseudopotential calculations, we study the energetics of various donor-pair defects which have been proposed as electrically deactivating donors in highly n-type Si. We find that a class of nearest-neighbor donor pairs such as d1 and DP(1) is energetically most favorable. Among donor-pair-vacancy-interstitial complexes, the DP(2)V-I defect forms a metastable configuration, with very low energy barriers of 0.03–0.06 eV for transforming into d2, which behaves as an electrically active donor. Thus, the formation of DP(2)V-I is more probable for samples grown at low temperatures, in good agreement with recent experiments. On the other hand, the DP(4)V-I defect is unstable against the formation of d4, with no energy barriers. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]