Interstitial boron defects in Si

A theoretical investigation is made into the structure and properties of complexes formed between boron and other common impurities in Si, namely hydrogen, oxygen and carbon. Particular emphasis is placed on identifying the centres with those observed experimentally. It is shown that B_iB_s, an electrically inert defect that can be identified with the infrared absorption Q-centre, can readily bind a hydrogen atom. B_iB_sH may then be responsible for the E_v+0.51 eV acceptor level seen in irradiated Si that contains hydrogen. B_iO_i has a (0/+) level close to E_c−0.23 eV and may be detected after the loss of B_i. The anneal of B_iO_i can lead to the formation of B_iC_s which is stable to similar to 400°C and has a level near E_v+0.29 eV.