Theoretical Study of Acceptor-Donor Complexes in 4H-SiC

The total energies and electronic structures of acceptor-donor complexes in 4H-SiC were investigated using ab initio calculation methods. Our calculations covered the A(2)D complex consisting of substitutional two-acceptor atoms from group-III elements and a nitrogen (N) donor atom. Results indicate some A(2)D complexes can exist stably, and solid solubilities of Al(2)N and Ga(2)N may be greatly enhanced. We also found that Ga(2)N introduces a shallower acceptor level compared to conventional acceptor atoms such as B and Al. Our results suggest that Ga(+)/N(+) co-implantation is one of the promising candidates for a doping method to realize low-resistivity p-type 4H-SiC. (C) 2008 The Japan Society of Applied Physics