Electrical data obtained from deep level transient spectroscopy investigations on deep defect centers in the 3C, 4H, and 6H SiC polytypes are reviewed. Emphasis is put on intrinsic defect centers observed in as‐grown material and subsequent to ion implantation or electron irradiation as well as on defect centers caused by doping with or implantation of transition metals (vanadium, titanium, chromium, and scandium).

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Possible defect structures, arising from the interaction of O 2 molecules with an ideal portion of the SiC/ SiO 2 interface, have been investigated systematically using density functional theory. Based on the calculated total energies and assuming thermal quasiequilibrium during oxidation, the most likely routes leading to complete oxidation have been determined. The defect structures produced along these routes will remain at the interface in significant concentration when stopping the oxidation process. The results obtained for their properties are well supported by experimental findings about the SiC/ SiO 2 interface. It is found that carbon-carbon bonds can explain most of the observed interface states but not the high density near the conduction band of 4H-SiC.

The adsorption and decomposition of acetylene on Si(100)-(2xl) have been studied in ultrahigh vacuum by Auger electron spectroscopy, temperature-programmed desorption, and changes in the partial pressure of acetylene as measured by a quadrupole mass spectrometer during the formation of a monolayer. Acetylene was found to chemisorb onto Si( 100)-(2X1) via a mobile precursor. The difference between the activation energy for desorption from the precursor and that for reaction from the precursor into the chemisorbed state was found to be (£d -£r) = 1.9 ± 0.6 kcal mol"1. At a low surface temperature, reaction from the precursor state dominates, giving a chemisorption probability of unity at submonolayer coverages. The saturated acetylene coverage is measured to be one C2H2 per Si2 dimer. Thermochemical arguments are presented, which indicate that acetylene bonds as a dispecies to dimer sites in which the Si-Si dimer bond has been cleaved. Chemisorbed acetylene was found to undergo two thermal reactions. A minor pathway (<5%) involves acetylene desorption, and a major pathway (>95%) involves the dissociation of acetylene to produce chemisorbed carbon and H2 (g). At temperatures above 800 K, the surface carbon begins to diffuse into the bulk of the silicon crystal.

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