+point defects were investigated by both methods.
+the interstitial carbon mmigration path was identified.
+it turned out that the diffusion barrier is drastically overestimated
+within the ea description.
+
+combinations of defects were investigated by first principles methods.
+the agglomeration of point defects is energetically favorable.
+however, substitutional carbon arises in all probability.
+even transitions from the ground state are very likely to occur.
+
+concerning the precipitation simulations, the problem of
+potential enhanced slow phase space propagation was discussed.
+high temperatures are assumed necessary to simulate ibs conditions.
+at low temperatures a dumbbell dominated structure is obatined
+whereas
+it is expected that
+Stretched structures of SiC were observed at elevated temperatures.
+it is thus concluded that
+substitutional carbon is heavily involved in the precipitation process.
+the role of the Si_i was outlined.
+
+in total, these results suggest,
+that cubic SiC precipitation occurs by successive agglomeration of Cs.
+
+slide 24
+
+finally, I would like to thank all of the people listed on this slide,
+categorized by location.
+
+thank you for your attention!
+
+
+
+
+
+slide X polytypes
+
+although the local order of the silicon and carbon atoms
+characterized by the tetrahedral bond is always the same,
+more than 250 different polytypes exist,
+which differ in the one-dimensional stacking sequence of
+identical, close-packed SiC bilayers,
+the stacking sequence of the most important polytypes is displayed here.
+the 3c polytype is the only cubic polytype.
+
+different polytypes exhibit different properties,
+which are listed in the table
+and compared to other technologically relevant semiconductor materials.
+SiC clearly outperforms silicon.
+among the different polytypes, the cubic phase shows the highest
+break down field and saturation drift velocity.
+additionally, these properties are isotropic.
+thus, the cubic polytype is considered most effective for highly efficient
+high-performance electronic devices.
+
+slide X silicon self interstitials
+
+in the following, structures and formation energies
+of silicon self-interstitial defects are shown.
+the classical potential and ab initio method predicts formation energies,
+which are within the same order of magnitude.
+however, discrepancies exist.
+quantum-mechanical results reveal the silicon 110 interstitial dumbbell (db)
+as the ground state closely followed by the hexagonal and tetrahedral
+configuration, which is the consensus view for silicon interstitials.
+in contrast, the ea potential favors the tetrahedral configuration,
+a known problem, which arises due to the cut-off
+underestimating the closely located second next neighbors.
+the hexagonal defect is not stable
+opposed to results of the authors of the potential.
+first, it seems to condense at the hexagonal site but suddenly
+begins to move towards a more favoarble position,
+close to the tetrahedral one but slightly displaced along all 3 coordinate axes.
+this energy is equal to the formation energy given in the original work.
+this artificial configuration, however, turns out to have negligible influence
+in finite temperature simulations due to a low migration barrier into the
+tetrahedral configuration.
+nevertheless, all these discrepancies have to be taken into account
+in the following investigations of defect combinations.
+
+slide X quantum mechanical details of 100 and bc