A first-principles study was made of the structure and dynamics of small As-interstitial complexes (AsI2, As2I2, AsI3 and As2I3) in crystalline Si. These complexes could be important components of stable As-interstitial clusters or played a key role in interstitial-mediated formation of As-vacancy clusters. Neutral AsI2 and As2I2 were identified as fast-diffusing species that contributed to As transient enhanced diffusion. It was demonstrated that the extended defect configuration As2I3ext was a stable configuration with a binding energy of 2.64eV. As2I3ext could serve as a nucleation site and facilitate the formation of larger As-interstitial clusters in the presence of excess Si interstitials and high As concentration. The implications of the findings on As transient enhanced diffusion and clustering were also considered and the role played by small As-interstitial complexes in ultra-shallow junction formation was highlighted.

First-Principles Studies of Small Arsenic Interstitial Complexes in Crystalline Silicon. Y.Kim, T.A.Kirichenko, N.Kong, G.Henkelman, S.K.Banerjee: Physical Review B, 2009, 79[7], 075201