Microscopic structures of Sb-H, Te-H, and Sn-H complexes in silicon

Abstract

The microscopic structures of hydrogen-antimony, -tellurium, and -tin complexes in silicon have been studied using first-principles total-energy calculations, in order to obtain a more definitive understanding of the various dopant-hydrogen complexes in n-type crystalline silicon. We find that for neutral SbH, TeH, and SnH complexes, the lowest-energy configurations are similar and of the type AB-Si (the H is located at the antibonding site of a Si atom that is adjacent to the impurity). The reaction SbH + H→SbH2 turns out to be exothermic. The results are consistent with recent experimental results using Mössbauer spectroscopy. For SbH2 various configurations are found that differ only slightly in energy. The lowest-energy configuration of SbH2 complexes exhibits electrical properties similar to those of substitutional Sb. This suggests that the formation of SbH2 not only competes with that of SbH and H*2, but may also electrically activate the sample.