The Mechanism of {113} Defect Formation in Silicon: Clustering of Interstitial–Vacancy Pairs Studied by In Situ High-Resolution Electron Microscope Irradiation

Abstract

Abstract:We report the direct visualization of point defect clustering in $113% planes of silicon crystal using a transmission electron microscope, which was supported by structural modeling and high-resolution electron microscope image simulations. In the initial stage an accumulation of nonbonded interstitial-vacancy~I-V! pairs stacked at a distance of 7.68 Å along neighboring atomic chains located on the $113% plane takes place. Further broadening of the $113% defect across its plane is due to the formation of planar fourfold coordinated defects~FFCDs! perpendicular to chains accumulating I-V pairs. Closely packed FFCDs create a sequence of eightfold rings in the $113% plane, providing sites for additional interstitials. As a result, the perfect interstitial chains are built on the $113% plane to create an equilibrium structure. Self-ordering of point defects driven by their nonisotropic strain fields is assumed to be the main force for point defect clustering in the $113% plane under the existence of an energy barrier for their recombination.

Shear-driven phase transformation in silicon nanowires

“…Numerous HRTEM investigations have been carried out to identify their complex structure. It was demonstrated that the formation of {113} defects is based on the aggregation of interstitials and vacancies during annealing of implanted zones at around 650°C-850 °C [25,26]. However, this is the first observation of these specific defects in Si after plastic deformation and it will be the object of further investigations to understand the mechanisms of formation in the present conditions.…”

Atomic structures and dynamic properties of dislocations in semiconductors: current progress and stagnation

“…Point defects dominant in thermal equilibrium at temperatures are thought to be vacancies rather than self-interstitials. Recently, Fedina et al reported clustering of vacancy and interstitial pairs for so-called {113}-defect formations during in situ HREM irradiation [62]. They found planar fourfold-coordinated defects in the process, though it remains unclear whether such kinds of point-like defects are detectable using that method.…”