The different behavior of nitrogen and phosphorus as n-type dopants in SiC

In this work, the experimentally observed differences in the behavior of nitrogen and phosphorus as n-type dopants in silicon carbide have been investigated within the framework of density functional theory. A key to the understanding of complex formation is the investigation of the dynamics of these dopant atoms. We have found essential differences in the recombination behavior of nitrogen and phosphorus atoms with vacancies. In contrast to nitrogen, which prefers to be built in on the carbon site exclusively (NC), our dynamical calculations show phosphorus to be built in on both substitutional lattice sites (PSi and PC). By this, PC-containing complexes should be considered as possible candidates for P-related electron paramagnetic resonance spectra in 6H-SiC which up to now have not been explained consistently. Furthermore, we explain why the formation of inactive complexes is likely in case of nitrogen but not in case of phosphorus