Imaging Structure and Impurities in the Core of Silicon Dislocations and Grain Boundaries: A High-Resolution Transmission Electron Microscopy and Computer Image Simulation Study

摘要

The core structure of silicon grain boundaries has been studied with high-resolution transmission electron microscopy (HRTEM). The atomistic nature of segregation sites in the diamond structure and potential HRTEM methods for their study have been evaluated. Plastic models with ''bond'' lengths selected to mimic the covalent bonds in silicon were constructed for silicon dislocations lying along <110> and <100> directions and <110> and <100> tilt grain boundaries in order to assist in prediction of potential defect core interstitial and substitutional segregation sites. Computer simulation of HRTEM images was applied to these models to assess the potential of HRTEM for imaging impurities at defects. In addition, HRTEM has been applied to the structural analysis of <110> and <100> tilt grain boundaries in silicon. The dislocations and grain boundaries examined can be described in terms of a small set of basic structural elements. These include perfect diamond structure 6-membered rings, boat-shaped rings, 5- and 17-membered rings, and elements possessing unpaired or reconstructed valence electrons. (ERA citation 11:020447)