Nitrogen related shallow thermal donors in silicon

Abstract

In this letter, the authors investigate the electrical properties of nitrogen related shallow thermal donor (STD) candidates and their concentrations under different doping conditions by means of density functional theory. Experimentally, the existence of STDs containing one nitrogen atom and both even and odd numbers of oxygen atoms has been proposed. However, so far first principles studies have not presented a candidate for the latter. Here, they show that the NO defect possesses a shallow donor level. Adding one or two more oxygen atoms results in the donor level to become shallower. The fraction of shallow nitrogen related donors to N dimers increases in material with low concentration of nitrogen.