Density-functional super-cell calculations were made of the electronic structure of the stacking faults which resulted from the glide of Shockley partials in 3C-, 4H- and 6H-SiC. It was found that both types of stacking faults in 4H-SiC, and 2 types of stacking fault in 6H-SiC, gave rise to band states which were strongly localized in the direction orthogonal to the stacking-fault plane. It was shown that it was possible to interpret this 1-dimensional localization as being a quantum-well confinement effect. It was also found that the third type of stacking fault in 6H-SiC, and the only stacking fault in 3C-SiC, did not give rise to states that were clearly separated from the band edges, but instead gave rise to quite strongly localized band states having energies very close to the band edges. It was suggested that these localized near-bandedge states were created by stacking-fault induced changes in the dipole moment which was associated with the hexagonal symmetry. The stacking-fault energies were also calculated by using the super-cell method and the axial next-nearest neighbor Ising model. Both theories agreed well with the low stacking-fault energies which were found experimentally.

Stacking Faults in 3C-, 4H- and 6H-SiC Polytypes Investigated by an ab initio Supercell Method. U.Lindefelt, H.Iwata, S.Öberg, P.R.Briddon: Physical Review B, 2003, 67[15], 155204 (12pp)