Induced defect levels of P and Al vacancy-complexes in 4 H-SiC: A hybrid functional study

摘要

The electronic behaviour of high-dose phosphorus implanted in 4 H-SiC is mainly desirable to obtained lower sheet resistance of 4 H-SiC. Al doping on the other hand acts as an acceptor, improves the dielectric properties of 4 H-SiC and has very low diffusivity in SiC. Using a hybrid density functional theory, we investigated the properties of Al and P defect-complexes in 4 H-SiC a wide band-gap semiconductor that is promising for applications in high-frequency and high-temperature electronic device. We show that vacancy-complexes formed by P-Si, and Al-Si, are more energetically stable than those formed by P-C and Al-C. The defects with silicon vacancy are predicted to experience more lattice distortion compared to those formed with carbon vacancy. While vacancy-complexes formed with P-S(i), or P-C and V-C induced double donor levels, vacancy-complex formed with substitution of P and V-Si, induced negative-U charge state ordering. The Al with V-C related vacancy-complexes induced deep single donor and acceptor levels, and Al with V-Si, induced only acceptor and negative-U ordering.