Open AccessCooperative chemical rebonding in the segregation of impurities in silicon grain boundaries
Author(s) -
A Maiti,
M F Chisholm,
S. J. Pennycook,
Sokrates T. Pantelides
Publication year - 1996
Language(s) - English
Resource type - Reports
DOI - 10.2172/432990
Subject(s) - grain boundary , materials science , dislocation , impurity , chemical physics , crystallography , condensed matter physics , silicon , grain boundary strengthening , chemistry , metallurgy , microstructure , physics , organic chemistry
With ab initio calculations the authors show that the experimentally observed large segregation energies of As at Si grain boundaries can be explained by the formation of isolated dimers or ordered chains of dimers of threefold-coordinated As along the cores of grain boundary dislocations. They also find the intriguing possibility that As segregation may drive structural transformation of certain grain boundaries. Recently, they have obtained the first atomic-resolution STEM images of As in a Si grain boundary, consistent with the formation of As dimers. Segregation energy of As dimers was found to be significantly higher in isolated dislocation cores, where larger site-variation in strain than in grain boundaries lead to further lowering of the electronic levels of As deep into the bandgap