concentration at $10 \, at. \%$ in a $500 \, nm$ thick
surface layer
\includegraphics[width=8cm]{multiple_impl_cp_e.eps}
+\begin{itemize}
+ \item Multiple energy ($180$-$10 \, keV$) $C^+$ $\rightarrow$ $Si$ implantation
+ \item $T_i=500 \, ^{\circ} \mathrm{C}$, to prevent amorphization
+\end{itemize}
\end{slide}
\begin{slide}