Theory of hyperfine active nitrogen complexes observed in 4H-SiC diodes

Nitrogen complexes have been implicated as defects that limit the performance of SiC-based electronics. Here, we use density functional methods to explore the properties of nitrogen vacancy complexes in bulk 4H-SiC. The stability, electronic levels and hyperfine signatures of defect complexes are reported. A nitrogen substitutional/carbon-antisite complex is found to be the strongest candidate for recently observed hyperfine active defects in 4H-SiC diodes.