A first-principles study was made of all the structurally different stacking faults which could be introduced by glide along the (00•1) basal plane in 3C-, 4H- and 6H-SiC based on the local-density approximation within the density-functional theory. Band-structure calculations revealed that both types of stacking faults in 4H-SiC and two of the three different types of stacking faults in 6H-SiC give rise to quasi 2-dimensional energy band states in the band gap at around 0.2eV below the lowest conduction band, thus being electrically active in n-type material. Although stacking faults, unlike point defects and surfaces, were not associated with broken or chemically perturbed bonds, a strong localization was found, within roughly 1 to 1.5nm perpendicular to the stacking fault plane, of the stacking fault gap state wave functions. It was found that this quantum-well-like feature of certain stacking faults in SiC could be understood in terms of the large conduction-band offsets between the cubic and hexagonal polytypes. Recent experimental results give qualitative support to the present results.

Localized Electronic States around Stacking Faults in Silicon Carbide. H.Iwata, U.Lindefelt, S.Öberg, P.R.Briddon: Physical Review B, 2002, 65[3], 033203 (4pp)