Defect levels induced by double substitution of B and N in 4H-SiC

Autor: Ezekiel Omotoso, Helga T. Danga, Emmanuel Igumbor, Walter E. Meyer
Rok vydání: 2019
Předmět:
Zdroj: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 442:41-46
ISSN: 0168-583X
DOI: 10.1016/j.nimb.2019.01.014
Popis: Studies of substitutional impurities in 4H-SiC play a major role in identifying the most enhanced defect levels induced. N and B substitution in 4H-SiC on separate studies reveal that the N Si induced negative-U charge state ordering while the B Si induced shallow acceptor level. In this report, in order to predict the most stable defect and its electrically active defect levels, the Heyd, Scuseria and Ernzerhof (HSE06) hybrid functional was used to model and predict the energetics and defect levels induced by double substitution of B and N pair ( N Si B C , N C B C , N Si B Si and N C B Si ) in a 4H-SiC. While both B and N substituted for C under equilibrium conditions is the most energetically favourable pair, the N and B both substituted for Si has a relatively high formation energy. The energies of the various configurations suggest that the substitution of B and N pair in 4H-SiC is always stable, and the N C B C is the most energetically favourable defect. While all the defects studied induced acceptor levels, only the N C B C and N Si B C induced shallow donor levels. The (0/−1) acceptor level induced by the defects is close to the conduction band minimum for the case of N C B C and N C B Si and deep lying middle of the band gap of 4H-SiC for the N Si B Si and N Si B C .
Databáze: OpenAIRE
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