+The tetrahedral and the <110> dumbbell self-interstitial configurations can be reproduced as observed in \cite{albe_sic_pot}.
+The formation energies are $3.4\, eV$ and $4.4\, eV$ respectively.
+However the hexagonal one is not stable opposed to what is presented in \cite{albe_sic_pot}.
+The atom moves towards an energetically more favorable position very close to the tetrahedral one but slightly displaced along the three coordinate axes.
+The formation energy of $4.0\, eV$ of this type of interstitial equals the result obtained in the reference for the hexagonal one.
+The same type of interstitial may arise using random insertions.
+In addition variations exist in which the displacement is only along two axes ($E_f=3.8\, eV$) or along a single axis ($E_f=3.6\, eV$) succesively approximating the tetrahedral configuration and formation energy.
+
+The tetrahedral and <110> dumbbel carbon interstitial configurations are stable.
+The formation energies are $2.7\, eV$ and $1.8\, eV$ respectively.
+Again the hexagonal one is found to be unstable.
+The interstitial atom moves to the more favorable <100> dumbbell position which has a formation energy of $0.5\, eV$.
+There is experimental evidence \cite{watkins76} of the existence of this configuration.
+This type of configuration is frequently observed for the random insertion runs and is assumed to be the lowest in energy.
+
+\begin{figure}[!h]
+ \begin{center}
+ \includegraphics[width=12cm]{../plot/diff_dep.ps}
+ \caption{Diffusion coefficients of a single carbon atom for different amount of Si selft interstitials}
+ \end{center}
+\end{figure}
+The influence of Si self-interstitials on the diffusion of a single carbon atom is displayed in Fig. 3.
+Diffusion coefficients for different amount of Si self-interstitials are shown.
+A slight increase is first observed in the case of 30 interstitial atoms.
+Further increasing the amount of interstitials leads to a tremendous decay of the diffusion coeeficient.
+Generally there is no long range diffusion of the carbon atom for a temperature of $450\, ^{\circ} \textrm{C}$.
+The maximal displacement of the carbon atom relativ to its insertion position is between 0.5 and 0.7 \AA.
+
+\begin{figure}[!h]
+ \begin{center}
+ \includegraphics[width=12cm]{../plot/foo_end.ps}
+ \includegraphics[width=12cm]{../plot/foo150.ps}
+ \caption{Pair correlation functions for Si-C and C-C bonds.
+ Carbon atoms are introduced into the whole simulation volume ({\color{red}-}), the region which corresponds to the size of a minimal SiC precipitate ({\color{green}-}) and the volume which contains the necessary amount of silicon for such a minimal precipitate ({\color{blue}-}).}
+ \end{center}
+\end{figure}
+Fig. 4 shows results of the simulation runs targeting the observation of precipitation events.
+The C-C pair correlation function suggests carbon nucleation for the simulation runs where carbon was inserted into the two smaller regions.
+The peak at $1.5\, \textrm{\AA}$ fits quite well the next neighbour distance of diamond.
+On the other hand the Si-C pair correlation function indicates formation of SiC bonds with an increased crystallinity for the simulation in which carbon is inserted into the whole simulation volume.
+There is more carbon forming Si-C bonds than C-C bonds.
+This gives suspect to the competition of Si-C and C-C bond formation in which the predominance of either of them depends on the method handling carbon insertion.
+
+\section*{Summary}
+The supposed conversion mechanism of heavily carbon doped silicon into silicon carbide is presented.
+Molecular dynamics simulation sequences to investigate interstitial configurations, the influence of interstitials on the atomic diffusion and the precipitation of SiC are proposed.
+The <100> C-Si dumbbel is reproducable by simulation and is the energetically most favorable configuration.
+The influence of silicon self-interstitials on the diffusion of a single carbon atom is demonstrated.
+Two competing bond formations, either Si-C or C-C, seem to coexist, where the strength of either of them depends on the size of the region in which carbon is introduced.
+
+\bibliography{../../bibdb/bibdb}