\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
+\usepackage{latexsym}
\usepackage{ae}
\usepackage{calc} % Simple computations with LaTeX variables
\usepackage{fancyvrb} % Fancy verbatim environments
\usepackage{pstricks} % PSTricks with the standard color package
+\usepackage{pstricks}
+\usepackage{pst-node}
+
+%\usepackage{epic}
+%\usepackage{eepic}
+
\usepackage{graphicx}
\graphicspath{{../img/}}
+\usepackage[setpagesize=false]{hyperref}
+
\usepackage{semcolor}
\usepackage{semlayer} % Seminar overlays
\usepackage{slidesec} % Seminar sections and list of slides
\articlemag{1}
+\special{landscape}
+
\begin{document}
\extraslideheight{10in}
-\slideframe{plain}
+\slideframe{none}
+
+\pagestyle{empty}
% specify width and height
\slidewidth 27.7cm
% shift it into visual area properly
\def\slideleftmargin{3.3cm}
-\def\slidetopmargin{0.0cm}
+\def\slidetopmargin{0.6cm}
\newcommand{\ham}{\mathcal{H}}
\newcommand{\pot}{\mathcal{V}}
\newcommand{\foo}{\mathcal{U}}
\newcommand{\vir}{\mathcal{W}}
+% itemize level ii
+\renewcommand\labelitemii{{\color{gray}$\bullet$}}
+
% topic
\begin{slide}
% contents
+% no contents for such a short talk!
+
+% start of contents
+
\begin{slide}
- \begin{center}
- {\bf
- Molecular dynamics simulation study\\
- of the silicon carbide precipitation process
+ {\large\bf
+ Motivation / Introduction
}
- \end{center}
\vspace{16pt}
- {\large\bf
- Outline
- }
+ Reasons for understanding the SiC precipitation process:
+
+ \begin{itemize}
+ \item 3C-SiC wide band gap semiconductor formation
+ \item Strained Si (no precipitation wanted!)
+ \end{itemize}
\vspace{16pt}
+ Si / 3C-SiC facts:
+
+ \begin{minipage}{8cm}
\begin{itemize}
- \item Motivation / Introduction
- \item Molecular dynamics simulation details
+ \item Unit cell:
\begin{itemize}
- \item Integrator, potential, ensemble control
- \item Simulation sequence
+ \item {\color{orange}fcc} $+$
+ \item {\color{gray}fcc shifted $1/4$ of volume diagonal}
\end{itemize}
- \item Results gained by simulation
- \begin{itemize}
- \item Carbon interstitials in silicon
- \item Existence of $SiC$-precipitates
- \end{itemize}
- \item Conclusion / Outlook
+ \item Lattice constants:
+ \[
+ 4a_{Si}\approx5a_{SiC}
+ \]
+ \item Silicon density:
+ \[
+ \frac{n_{SiC}}{n_{Si}}=97,66\,\%
+ \]
\end{itemize}
+ \end{minipage}
+ \hspace{8pt}
+ \begin{minipage}{4cm}
+ \includegraphics[width=4cm]{sic_unit_cell.eps}
+ \end{minipage}
+
\end{slide}
-% start of contents
+ \small
+\begin{slide}
+
+ {\large\bf
+ Motivation / Introduction
+ }
+
+ \small
+ \vspace{6pt}
+
+ Supposed conversion mechanism of heavily carbon doped Si into SiC:
+
+ \vspace{8pt}
+
+ \begin{minipage}{3.8cm}
+ \includegraphics[width=3.7cm]{sic_prec_seq_01.eps}
+ \end{minipage}
+ \hspace{0.6cm}
+ \begin{minipage}{3.8cm}
+ \includegraphics[width=3.7cm]{sic_prec_seq_02.eps}
+ \end{minipage}
+ \hspace{0.6cm}
+ \begin{minipage}{3.8cm}
+ \includegraphics[width=3.7cm]{sic_prec_seq_03.eps}
+ \end{minipage}
+
+ \vspace{8pt}
+
+ \begin{minipage}{3.8cm}
+ Formation of C-Si dumbbells on regular c-Si lattice sites
+ \end{minipage}
+ \hspace{0.6cm}
+ \begin{minipage}{3.8cm}
+ Agglomeration into large clusters (embryos)\\
+ \end{minipage}
+ \hspace{0.6cm}
+ \begin{minipage}{3.8cm}
+ Precipitation of 3C-SiC + Creation of interstitials\\
+ \end{minipage}
+
+ \vspace{12pt}
+
+ Experimentally observed:
+ \begin{itemize}
+ \item Minimal diameter of precipitation: 4 - 5 nm
+ \item Equal orientation of Si and SiC (hkl)-planes
+ \end{itemize}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Simulation details
+ }
+
+ \vspace{12pt}
+
+ MD basics:
+ \begin{itemize}
+ \item Microscopic description of N particle system
+ \item Analytical interaction potential
+ \item Hamilton's equations of motion as propagation rule\\
+ in 6N-dimensional phase space
+ \item Observables obtained by time average
+ \end{itemize}
+
+ \vspace{12pt}
+
+ Application details:
+ \begin{itemize}
+ \item Integrator: Velocity Verlet, timestep: $1\, fs$
+ \item Ensemble: NVT, Berendsen thermostat, $\tau=100.0$
+ \item Potential: Tersoff-like bond order potential\\
+ \[
+ E = \frac{1}{2} \sum_{i \neq j} \pot_{ij}, \quad
+ \pot_{ij} = f_C(r_{ij}) \left[ f_R(r_{ij}) + b_{ij} f_A(r_{ij}) \right]
+ \]
+ \begin{center}
+ {\scriptsize P. Erhart and K. Albe. Phys. Rev. B 71 (2005) 035211}
+ \end{center}
+ \end{itemize}
+
+ \begin{picture}(0,0)(-240,-70)
+ \includegraphics[width=5cm]{tersoff_angle.eps}
+ \end{picture}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Simulation details
+ }
+
+ \vspace{8pt}
+
+ Interstitial simulations:
+
+ \vspace{8pt}
+
+ \begin{pspicture}(0,0)(7,8)
+ \rput(3.5,7){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=green]{
+ \parbox{7cm}{
+ \begin{itemize}
+ \item Initial configuration: $9\times9\times9$ unit cells Si
+ \item Periodic boundary conditions
+ \item $T=0 \, K$
+ \end{itemize}
+ }}}}
+\rput(3.5,3.5){\rnode{insert}{\psframebox{
+ \parbox{7cm}{
+ Insertion of C / Si atom:
+ \begin{itemize}
+ \item $(0,0,0)$ $\rightarrow$ {\color{red}tetrahedral}
+ \item $(-1/8,-1/8,1/8)$ $\rightarrow$ {\color{green}hexagonal}
+ \item $(-1/8,-1/8,-1/4)$, $(-1/4,-1/4,-1/4)$\\
+ $\rightarrow$ {\color{magenta}110 dumbbell}
+ \item random positions (critical distance check)
+ \end{itemize}
+ }}}}
+ \rput(3.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=cyan]{
+ \parbox{3.5cm}{
+ Relaxation time: $2\, ps$
+ }}}}
+ \ncline[]{->}{init}{insert}
+ \ncline[]{->}{insert}{cool}
+ \end{pspicture}
+
+ \begin{picture}(0,0)(-210,-45)
+ \includegraphics[width=6cm]{unit_cell.eps}
+ \end{picture}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Results
+ } - Si self-interstitial runs
+
+ \small
+
+ \begin{minipage}[t]{4.3cm}
+ \underline{Tetrahedral}\\
+ $E_f=3.41\, eV$\\
+ \includegraphics[width=3.8cm]{si_self_int_tetra_0.eps}
+ \end{minipage}
+ \begin{minipage}[t]{4.3cm}
+ \underline{110 dumbbell}\\
+ $E_f=4.39\, eV$\\
+ \includegraphics[width=3.8cm]{si_self_int_dumbbell_0.eps}
+ \end{minipage}
+ \begin{minipage}[t]{4.3cm}
+ \underline{Hexagonal} \hspace{4pt}
+ \href{../video/si_self_int_hexa.avi}{$\rhd$}\\
+ $E_f^{\star}\approx4.48\, eV$ (unstable!)\\
+ \includegraphics[width=3.8cm]{si_self_int_hexa_0.eps}
+ \end{minipage}
+
+ \underline{Random insertion}
+
+ \begin{minipage}{4.3cm}
+ $E_f=3.97\, eV$\\
+ \includegraphics[width=3.8cm]{si_self_int_rand_397_0.eps}
+ \end{minipage}
+ \begin{minipage}{4.3cm}
+ $E_f=3.75\, eV$\\
+ \includegraphics[width=3.8cm]{si_self_int_rand_375_0.eps}
+ \end{minipage}
+ \begin{minipage}{4.3cm}
+ $E_f=3.56\, eV$\\
+ \includegraphics[width=3.8cm]{si_self_int_rand_356_0.eps}
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Results
+ } - Carbon interstitial runs
+
+ \small
+
+ \begin{minipage}[t]{4.3cm}
+ \underline{Tetrahedral}\\
+ $E_f=2.67\, eV$\\
+ \includegraphics[width=3.8cm]{c_in_si_int_tetra_0.eps}
+ \end{minipage}
+ \begin{minipage}[t]{4.3cm}
+ \underline{110 dumbbell}\\
+ $E_f=1.76\, eV$\\
+ \includegraphics[width=3.8cm]{c_in_si_int_dumbbell_0.eps}
+ \end{minipage}
+ \begin{minipage}[t]{4.3cm}
+ \underline{Hexagonal} \hspace{4pt}
+ \href{../video/c_in_si_int_hexa.avi}{$\rhd$}\\
+ $E_f^{\star}\approx5.6\, eV$ (unstable!)\\
+ \includegraphics[width=3.8cm]{c_in_si_int_hexa_0.eps}
+ \end{minipage}
+
+ \underline{Random insertion}
+
+ \footnotesize
+
+\begin{minipage}[t]{3.3cm}
+ $E_f=0.47\, eV$\\
+ \includegraphics[width=3.3cm]{c_in_si_int_001db_0.eps}
+ \begin{picture}(0,0)(-15,-3)
+ 001 dumbbell
+ \end{picture}
+\end{minipage}
+\begin{minipage}[t]{3.3cm}
+ $E_f=1.62\, eV$\\
+ \includegraphics[width=3.2cm]{c_in_si_int_rand_162_0.eps}
+\end{minipage}
+\begin{minipage}[t]{3.3cm}
+ $E_f=2.39\, eV$\\
+ \includegraphics[width=3.1cm]{c_in_si_int_rand_239_0.eps}
+\end{minipage}
+\begin{minipage}[t]{3.0cm}
+ $E_f=3.41\, eV$\\
+ \includegraphics[width=3.3cm]{c_in_si_int_rand_341_0.eps}
+\end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Simulation details
+ }
+
+ \small
+
+ \vspace{8pt}
+
+ SiC precipitation simulations:
+
+ \vspace{8pt}
+
+ \begin{pspicture}(0,0)(12,8)
+ % nodes
+ \rput(3.5,6.5){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=green]{
+ \parbox{7cm}{
+ \begin{itemize}
+ \item Initial configuration: $31\times31\times31$ unit cells Si
+ \item Periodic boundary conditions
+ \item $T=450\, ^{\circ}C$
+ \item Equilibration of $E_{kin}$ and $E_{pot}$ for $600\, fs$
+ \end{itemize}
+ }}}}
+ \rput(3.5,3.2){\rnode{insert}{\psframebox[fillstyle=solid,fillcolor=red]{
+ \parbox{7cm}{
+ Insertion of $6000$ carbon atoms at constant\\
+ temperature into:
+ \begin{itemize}
+ \item Total simulation volume {\pnode{in1}}
+ \item Volume of minimal SiC precipitation {\pnode{in2}}
+ \item Volume of necessary amount of Si {\pnode{in3}}
+ \end{itemize}
+ }}}}
+ \rput(3.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=cyan]{
+ \parbox{3.5cm}{
+ Cooling down to $20\, ^{\circ}C$
+ }}}}
+ \ncline[]{->}{init}{insert}
+ \ncline[]{->}{insert}{cool}
+ \psframe[fillstyle=solid,fillcolor=white](7.5,1.8)(13.5,7.8)
+ \psframe[fillstyle=solid,fillcolor=lightgray](9,3.3)(12,6.3)
+ \psframe[fillstyle=solid,fillcolor=gray](9.25,3.55)(11.75,6.05)
+ \rput(7.9,4.8){\pnode{ins1}}
+ \rput(9.22,4.4){\pnode{ins2}}
+ \rput(10.5,4.8){\pnode{ins3}}
+ \ncline[]{->}{in1}{ins1}
+ \ncline[]{->}{in2}{ins2}
+ \ncline[]{->}{in3}{ins3}
+ \end{pspicture}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Very first results of the SiC precipitation runs
+ }
+
+ \footnotesize
+
+ \begin{minipage}[b]{6.9cm}
+ \includegraphics[width=6.3cm]{../plot/sic_prec_energy.ps}
+ \includegraphics[width=6.3cm]{../plot/sic_prec_temp.ps}
+ \end{minipage}
+ \begin{minipage}[b]{5.5cm}
+ \begin{itemize}
+ \item {\color{red} Total simulation volume}
+ \item {\color{green} Volume of minimal SiC precipitation}
+ \item {\color{blue} Volume of necessary amount of Si}
+ \end{itemize}
+ \vspace{40pt}
+ \includegraphics[width=6.3cm]{../plot/foo150.ps}
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Very first results of the SiC precipitation runs
+ }
+
+ \begin{minipage}[t]{6.9cm}
+ \includegraphics[width=6.3cm]{../plot/sic_pc.ps}
+ \includegraphics[width=6.3cm]{../plot/foo_end.ps}
+ \hspace{12pt}
+ \end{minipage}
+ \begin{minipage}[c]{5.5cm}
+ \includegraphics[width=6.0cm]{sic_si-c-n.eps}
+ \end{minipage}
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Summary / Outlook
+ }
+
+\vspace{24pt}
+
+\begin{itemize}
+ \item Importance of understanding the SiC precipitation mechanism
+ \item Interstitial configurations in silicon using the Albe potential
+ \item Indication of SiC precipitation
+\end{itemize}
+
+\vspace{24pt}
+
+\begin{itemize}
+ \item Displacement and stress calculations
+ \item Refinement of simulation sequence to create 3C-SiC
+ \item Analyzing self-designed Si/SiC interface
+\end{itemize}
+
+\end{slide}
\end{document}
projects / lectures / latex.git / blobdiff