Using density functional theory calculations, we examined the structure and stability of extendable self-interstitial cluster configurations (I n,n=12,16) with four-atom periodicity in crystalline silicon under biaxial strain (-4%ε4%) on Si(100). In the absence of strain, the ground state configurations of I12 and I16 share a common structure (I12 -like) with C2h symmetry and a four-atom repeating unit; however, we identified an extended configuration based on I4 (D2d symmetry) cluster aggregates [(I4 m (m=3,4)] along 〈 110 〉 that is more favorable under certain magnitudes of strain. While both the I12 -like and (I4m configurations exhibit relative stabilities that are a function of both strain and orientation, the larger (I4m orientation effect is the primary reason that these structures are preferred in both highly tensile and highly compressive environments. This suggests that I4 derivatives may participate in the growth transition of Si self-interstitial clusters in the compact-to-extended size regime (10n20) under strain.
|Journal||Applied Physics Letters|
|State||Published - 2009|