Boron-Silicon complex defects in GaAs: An ab initio study

First principles calculations have been performed to investigate defect equilibria of the silicon-boron pair complex (Si-B) in a GaAs matrix. For several charge states, the formation energies were evaluated within the Car-Parrinello scheme considering cation and anion substitutional site defects. The calculations, including the full relaxation of all ionic coordinates, investigate native defects and isolated substitutional silicon (Si) and boron (B) impurities. The obtained formation energies are used to calculate the impurity concentration for different growth conditions. These results can be used to estimate the effect of different thermal profiles on the distribution and electrical state of Si and B defects, which is interesting for classical process simulations. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3561373]