\background{.40 .48 .71}{.99 .99 .99}{0.5}
\newrgbcolor{si-yellow}{.6 .6 0}
+\newrgbcolor{hb}{0.75 0.77 0.89}
+\newrgbcolor{lbb}{0.75 0.8 0.88}
+\newrgbcolor{lachs}{1.0 .93 .81}
% Groesse der einzelnen Spalten als Anteil der Gesamt-Textbreite
\renewcommand{\columnfrac}{.31}
\newcommand{\pot}{\mathcal{V}}
% header
-\vspace{-18cm}
+\vspace{-18.5cm}
\begin{header}
\centerline{{\Huge \bfseries Molecular dynamics simulation
of defect formation and precipitation}}
\begin{poster}
-%\vspace{-6cm}
+\vspace{-1cm}
\begin{pcolumn}
\begin{pbox}
\section*{Motivation}
- {\bf Reasons for understanding the 3C-SiC precipitation process}
+ {\bf Importance of the 3C-SiC precipitation process in silicon}
\begin{itemize}
- \item Significant technological progress
- in 3C-SiC wide band gap semiconductor thin film formation [1].
- \item New perspectives for processes relying upon prevention of
- precipitation, e.g. fabrication of strained pseudomorphic
- $\text{Si}_{1-y}\text{C}_y$ heterostructures [2].
+ \item SiC is a promissing wide band gap material for high-temperature,
+ high-power. high-frequency semiconductor devices [1].
+ \item 3C-SiC epitaxial thin film formation on Si requires detailed
+ knowledge of SiC nucleation.
+ \item Fabrication of high carbon doped, strained pseudomorphic
+ $\text{Si}_{1-y}\text{C}_y$ layers requires suppression of
+ 3C-SiC nucleation [2].
\end{itemize}
{\tiny
[1] J. H. Edgar, J. Mater. Res. 7 (1992) 235.}\\
[2] J. W. Strane, S. R. Lee, H. J. Stein, S. T. Picraux,
J. K. Watanabe, J. W. Mayer, J. Appl. Phys. 79 (1996) 637.}
\end{pbox}
+ \vspace{-0.45cm}
\begin{pbox}
\section*{Crystalline silicon and cubic silicon carbide}
{\bf Lattice types and unit cells:}
\includegraphics[width=10cm]{sic_unit_cell.eps}
\end{minipage}
\end{pbox}
+ \vspace{-0.45cm}
\begin{pbox}
\section*{Supposed Si to 3C-SiC conversion}
{\bf Schematic of the conversion mechanism}\\\\
- \begin{minipage}{7.8cm}
- \includegraphics[width=7.7cm]{sic_prec_seq_01.eps}
+ \begin{minipage}[c]{8.8cm}
+ \includegraphics[width=8.0cm]{sic_prec_seq_01.eps}
\end{minipage}
- \hspace{0.6cm}
- \begin{minipage}{7.8cm}
- \includegraphics[width=7.7cm]{sic_prec_seq_02.eps}
+ \begin{minipage}[c]{8.8cm}
+ \includegraphics[width=8.0cm]{sic_prec_seq_02.eps}
\end{minipage}
- \hspace{0.6cm}
- \begin{minipage}{7.8cm}
- \includegraphics[width=7.7cm]{sic_prec_seq_03.eps}
+ \begin{minipage}[c]{8.1cm}
+ \includegraphics[width=8.0cm]{sic_prec_seq_03.eps}
\end{minipage}
\vspace{1cm}
\begin{enumerate}
\vspace{1cm}
{\bf Experimental observations} [3]
\begin{itemize}
- \item Minimal diameter of precipitation: 2 - 4 nm
+ \item Minimal radius of precipitates: 2 - 4 nm
\item Equal orientation of c-Si and 3C-SiC (hkl)-planes
\end{itemize}
{\tiny
[3] J. K. N. Lindner, Appl. Phys. A 77 (2003) 27.
}
\end{pbox}
+ \vspace{-0.45cm}
\begin{pbox}
\section*{Simulation details}
{\bf MD basics:}
\begin{minipage}{15cm}
{\small
\begin{pspicture}(0,0)(14,14)
- \rput(7,12.5){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=green]{
+ \rput(7,12.5){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
\parbox{14cm}{
\begin{itemize}
\item Initial configuration: $9\times9\times9$ unit cells Si
\item random positions (critical distance check)
\end{itemize}
}}}}
- \rput(7,1.5){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=cyan]{
+ \rput(7,1.5){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=lbb]{
\parbox{7cm}{
Relaxation time: 2 ps
}}}}
{\small
\begin{pspicture}(0,0)(30,13)
% nodes
- \rput(7.5,11){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=green]{
+ \rput(7.5,11){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
\parbox{15cm}{
\begin{itemize}
\item Initial configuration: $31\times31\times31$ unit cells Si
\item Equilibration of $E_{kin}$ and $E_{pot}$
\end{itemize}
}}}}
- \rput(7.5,5){\rnode{insert}{\psframebox[fillstyle=solid,fillcolor=red]{
+ \rput(7.5,5){\rnode{insert}{\psframebox[fillstyle=solid,fillcolor=lachs]{
\parbox{15cm}{
Insertion of 6000 carbon atoms at constant\\
temperature into:
\item Volume of necessary amount of Si $V_3$
\end{itemize}
}}}}
- \rput(7.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=cyan]{
+ \rput(7.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=lbb]{
\parbox{8cm}{
Cooling down to $20\, ^{\circ}\textrm{C}$
}}}}
or diamond\\
$\Rightarrow$ Formation of strong C-C bonds
(almost only for high C concentrations)
+ \item Si-C peak at 0.19 nm similar to next neighbour distance in 3C-SiC
\item C-C peak at 0.31 nm equals C-C distance in 3C-SiC\\
(due to concatenated, differently oriented
\flq100\frq{} dumbbell interstitials)
- \item Si-Si shows non-zero g(r) values around 0.31 nm
+ \item Si-Si shows non-zero g(r) values around 0.31 nm like in 3C-SiC\\
and a decrease at regular distances\\
(no clear peak,
interval of enhanced g(r) corresponds to C-C peak width)
- \item Si-C peak at 0.19 nm similar to next neighbour distance in 3C-SiC
\item Low C concentration (i.e. $V_1$):
The \flq100\frq{} dumbbell configuration
\begin{itemize}
}
\end{pbox}
- %\vspace{-0.5cm}
+ \vspace{-2cm}
\begin{pbox}
\section*{Conclusion}
\begin{itemize}
3C-SiC formation
\end{itemize}
\end{pbox}
+ \vspace{-2cm}
+ \begin{pbox}
+ One of us (F. Z.) wants to acknowledge financial support by the\\
+ {\bf Bayerische Forschungsstiftung} (DPA-61/05).
+ \end{pbox}
\end{pcolumn}
\end{poster}
projects / lectures / latex.git / commitdiff