{111} and (311) rod-like defects in silicon ion implanted silicon

Rodlike defects in Si ion implanted Si have been studied by transmission electron microscopy and molecular dynamics calculations. Three aspects of these defects are presented here: (1) The defects with {111} habit planes have been identified and the interstitial nature of these defects has been confirmed by matching of the experimental and the calculated images based on the model established by atomistic calculations. (2) The defects with {311} habit planes have complicated high resolution electron microscopy images. This is explained by the coexistence of the Tan model and the Takeda model along an interstitial chain. A bond reconstruction is involved to transform the Tan model into the Takeda model. The energy barrier for this reconstruction is about 1.5 eV. (3) The early stage of the formation of a <011> interstitial chain has been studied by molecular dynamics calculations, when two interstitial atoms form a dimer an interstitial chain with a unit length of the Tan model or the Takeda model is formed, leaving two dangling bonds at two ends promoting other interstitial atoms to stick on to the dimer along the <011> direction.