Theory of substitutional carbon and boron in silicon

Publisher Website
Google Scholar
Abstract
Local density functional theory is used to evaluate the structures, vibrational frequencies and effective charges of the substitutional impurities C and B- in silicon. The method uses a 71 atom H-terminated cluster with Gaussian basis functions. The authors find the B-Si length to be 2.097 AA and the triplet local mode at 635 cm-1, which is within 12 cm-1 of the observed one. The C-Si length and triplet mode are 2.101 AA and 561 cm-1 respectively. This frequency is within 50 cm-1 of the observed local mode. The effective charges on the impurities show that substitutional C leads to twice as much local mode absorption as an equal concentration of B-.