\chapter{Review of the silicon carbon compound}
\label{chapter:sic_rev}

\section{Structure, properties and applications of silicon carbide}

The phase diagram of the C/Si system is shown in figure~\ref{fig:sic:si-c_phase}.
The stoichiometric composition of silicon and carbon termed silicon carbide (SiC) is the only chemical stable compound in the C/Si system \cite{scace59}.
\begin{figure}[ht]
\begin{center}
\includegraphics[width=12cm]{si-c_phase.eps}
\end{center}
\caption[Phase diagram of the C/Si system.]{Phase diagram of the C/Si system \cite{scace59}.}
\label{fig:sic:si-c_phase}
\end{figure}
SiC was first discovered by Henri Moissan in 1893 when he observed brilliant sparkling crystals while examining rock samples from a meteor crater in Arizona.
He mistakenly identified these crystals as diamond.
Although they might have been considered \glqq diamonds from space\grqq{} Moissan identified them as SiC in 1904 \cite{moissan04}.
In mineralogy SiC is still referred to as moissanite in honor of its discoverer.
It is extremely rare and almost impossible to find in nature.

Each of the four sp$^3$ hybridized orbitals of the Si atom overlaps with one of the four sp$^3$ hybridized orbitals of the four surrounding C atoms and vice versa.
This results in fourfold coordinated covalent $\sigma$ bonds of equal length and strength for each atom with its neighbours.
Although the local order of Si and C next neighbour atoms characterized by the tetrahedral bonding is the same, more than 250 different types of structures called polytypes of SiC exist \cite{fischer90}.
The polytypes differ in the one-dimensional stacking sequence of identical, close-packed SiC bilayers.
\begin{figure}[ht]
\begin{center}
\includegraphics[width=12cm]{polytypes.eps}
\end{center}
\caption{Stacking sequence of SiC bilayers of the most common polytypes of SiC (from left to right): 3C, 2H, 4H and 6H.}
\label{fig:sic:polytypes}
\end{figure}
Figure~\ref{fig:sic:polytypes} shows the stacking sequence of the most common and technologically most important SiC polytypes, which are the cubic (3C) and hexagonal (2H, 4H and 6H) polytypes.

\begin{table}[ht]
\begin{center}
\begin{tabular}{l c c c c c c}
\hline
\hline
 & 3C-SiC & 4H-SiC & 6H-SiC & Si & GaN & Diamond\\
\hline
Hardness [Mohs] & \multicolumn{3}{c}{------ 9.6 ------}& 6.5 & - & 10 \\
Band gap [eV] & 2.36 & 3.23 & 3.03 & 1.12 & 3.39 & 5.5 \\
Break down field$^{\text{A}}$ [$10^6$ V/cm] & 4 & 3 & 3.2 & 0.6 & 5 & 10 \\
Saturation drift velocity$^{\text{A}}$ [$10^7$ cm/s] & 2.5 & 2.0 & 2.0 & 1 & 2.7 & 2.7 \\
Electron mobility$^{\text{B}}$ [cm$^2$/Vs] & 800 & 900 & 400 & 1100 & 900 & 2200 \\
Hole mobility$^{\text{B}}$ [cm$^2$/Vs] & 320 & 120 & 90 & 420 & 150 & 1600 \\
Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\
\hline
\hline
\end{tabular}
\end{center}
\caption[Properties of SiC polytypes and other semiconductor materials.]{Properties of SiC polytypes and other semiconductor materials. Doping concentrations are $10^{16}\text{ cm}^{-3}$ (A) and $10^{17}\text{ cm}^{-3}$ (B) respectively. References: \cite{wesch96,casady96}. {\color{red}Todo: add more refs + check all values!}}
\label{table:sic:properties}
\end{table}
Different polytypes of SiC exhibit different properties.
Some of the key properties are listed in table~\ref{table:sic:properties} and compared to other technologically relevant semiconductor materials.
Despite the low carrier mobilities for low electric fields SiC outperforms Si concerning all other properties.
The wide band gap ... light emitting diodes ... first blue led ... but GaN direct band gap semiconductor ...
However ... combine all electr properties ... high-* .. .devices diodes, inverters ... 
break down field and high thermal conductivity ... high-densea and high-power ...
high saturation drift velocity high-frequency ...
Mechanical stability almost like diamond ...
Chemical inert, low neutron capture foobar ... radiation hardness

Since in this work 3C-SiC unit cell ... two fcc lattices ...


\section{Fabrication of silicon carbide}

\section{Ion beam synthesis of cubic silicon carbide}

\section{Substoichiometric concentrations of carbon in crystalline silicon}

\section{Assumed precipitation mechanism of cubic silicon carbide in silicon}
\label{section:assumed_prec}

