From 3e27513b94aa60a22f2a24fae725617642e4fb0a Mon Sep 17 00:00:00 2001 From: hackbard Date: Thu, 17 Jun 2010 11:20:23 +0200 Subject: [PATCH] sec checkin (only small mods missing) --- posic/talks/seminar_2010.tex | 151 +++++++++++++++++++++++++++++++++-- 1 file changed, 143 insertions(+), 8 deletions(-) diff --git a/posic/talks/seminar_2010.tex b/posic/talks/seminar_2010.tex index b76a6a8..402a2c8 100644 --- a/posic/talks/seminar_2010.tex +++ b/posic/talks/seminar_2010.tex @@ -1,6 +1,6 @@ \pdfoutput=0 -%\documentclass[landscape,semhelv,draft]{seminar} -\documentclass[landscape,semhelv]{seminar} +\documentclass[landscape,semhelv,draft]{seminar} +%\documentclass[landscape,semhelv]{seminar} \usepackage{verbatim} \usepackage[greek,german]{babel} @@ -314,6 +314,19 @@ Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\ } \end{minipage} \end{picture} + \begin{picture}(0,0)(-230,-35) + \framebox{ + {\footnotesize\color{blue}\bf Hex: micropipes along c-axis} + } + \end{picture} + \begin{picture}(0,0)(-230,-10) + \framebox{ + \begin{minipage}{3cm} + {\footnotesize\color{blue}\bf 3C-SiC fabrication\\ + less advanced} + \end{minipage} + } + \end{picture} \end{slide} @@ -1971,7 +1984,7 @@ $\Longrightarrow$ \begin{minipage}{5cm} Introduced C (defects)\\ $\rightarrow$ reduction of transition point\\ -$\rightarrow$ melting even at $T_{\text{m}}$ +$\rightarrow$ melting already at $T_{\text{m}}$ \end{minipage} } @@ -2060,7 +2073,8 @@ y=\left(\frac{1}{2} \right)^{1/3}a_{\text{Si}} \item Spherical topotactically aligned precipitate\\ $r=3.0\text{ nm}$ $\Leftrightarrow$ $\approx$ 5500 C atoms \item Create c-Si but skipped inside sphere of radius $x$ - \item Create 3C-SiC inside sphere of radius $x$ and lattice constant $y$ + \item Create 3C-SiC inside sphere of radius $x$\\ + and lattice constant $y$ \item Strong coupling to heat bath ($T=20\,^{\circ}\mathrm{C}$) \end{itemize} \end{minipage} @@ -2076,28 +2090,149 @@ y=\left(\frac{1}{2} \right)^{1/3}a_{\text{Si}} \item Slight increase of c-Si lattice constant! \item C-C peaks (imply same distanced Si-Si peaks) \begin{itemize} - \item New peak at 0.307 nm: NN in 3C-SiC + \item New peak at 0.307 nm: 2$^{\text{nd}}$ NN in 3C-SiC \item Bumps ({\color{green}$\downarrow$}): 4$^{\text{th}}$ and 6$^{\text{th}}$ NN \end{itemize} \item 3C-SiC lattice constant: 4.34 \AA (bulk: 4.36 \AA)\\ $\rightarrow$ compressed precipitate \item Interface tension:\\ - 20.15 eV/nm$^2$ or $3.23 \times 10^{-4}$ J/cm$^2$ + 20.15 eV/nm$^2$ or $3.23 \times 10^{-4}$ J/cm$^2$\\ + (literature: $2 - 8 \times 10^{-4}$ J/cm$^2$) \end{itemize} \end{minipage} \end{slide} +\begin{slide} + + {\large\bf + Investigation of a silicon carbide precipitate in silicon + } + + \footnotesize + +\begin{minipage}{7cm} +\underline{Appended annealing steps} +\begin{itemize} + \item artificially constructed interface\\ + $\rightarrow$ allow for rearrangement of interface atoms + \item check SiC stability +\end{itemize} +\underline{Temperature schedule} +\begin{itemize} + \item rapidly heat up structure up to $2050\,^{\circ}\mathrm{C}$\\ + (75 K/ps) + \item slow heating up to $1.2\cdot T_{\text{m}}=2940\text{ K}$ + by 1 K/ps\\ + $\rightarrow$ melting at around 2840 K + (\href{../video/sic_prec_120.avi}{$\rhd$}) + \item cooling down structure at 100 \% $T_{\text{m}}$ (1 K/ps)\\ + $\rightarrow$ no energetically more favorable struture +\end{itemize} +\end{minipage} +\begin{minipage}{6cm} +\includegraphics[width=6.7cm]{fe_and_t_sic.ps} +\end{minipage} + +\begin{minipage}{4cm} +\includegraphics[width=4cm]{sic_prec/melt_01.eps} +\end{minipage} +\begin{minipage}{0.4cm} +$\rightarrow$ +\end{minipage} +\begin{minipage}{4cm} +\includegraphics[width=4cm]{sic_prec/melt_02.eps} +\end{minipage} +\begin{minipage}{0.4cm} +$\rightarrow$ +\end{minipage} +\begin{minipage}{4cm} +\includegraphics[width=4cm]{sic_prec/melt_03.eps} +\end{minipage} + +\end{slide} + \begin{slide} {\large\bf Summary / Conclusion / Outlook } - \small + \scriptsize - +\vspace{0.1cm} + +\framebox{ +\begin{minipage}{12.9cm} + \underline{Defects} + \begin{itemize} + \item Summary \& conclusion + \begin{itemize} + \item Point defects excellently / fairly well described + by QM / classical potential simulations + \item Identified migration path explaining + diffusion and reorientation experiments + \item Agglomeration of point defects energetically favorable + \item C$_{\text{sub}}$ favored conditions (conceivable in IBS) + \end{itemize} + \item Todo + \begin{itemize} + \item Discussions concerning interpretation of QM results (Paderborn) + \item Compare migration barrier of + \hkl<1 1 0> Si and C-Si \hkl<1 0 0> dumbbell + \item Combination: Vacancy \& \hkl<1 1 0> Si self-interstitial \& + C-Si \hkl<1 0 0> dumbbell (IBS) + \end{itemize} + \end{itemize} +\end{minipage} +} + +\vspace{0.2cm} + +\framebox{ +\begin{minipage}[t]{6.2cm} + \underline{Pecipitation simulations} + \begin{itemize} + \item Summary \& conclusion + \begin{itemize} + \item Low T + $\rightarrow$ C-Si \hkl<1 0 0> dumbbell\\ + dominated structure + \item High T $\rightarrow$ C$_{\text{sub}}$ dominated structure + \item High C concentration\\ + $\rightarrow$ amorphous SiC like phase + \end{itemize} + \item Todo + \begin{itemize} + \item Accelerated method: self-guided MD + \item Activation relaxation technique + \item Constrainted transition path + \end{itemize} + \end{itemize} +\end{minipage} +} +\framebox{ +\begin{minipage}[t]{6.2cm} + \underline{Constructed 3C-SiC precipitate} + \begin{itemize} + \item Summary \& conclusion + \begin{itemize} + \item Small / stable / compressed 3C-SiC\\ + precipitate in slightly stretched\\ + c-Si matrix + \item Interface tension matches experiemnts + \end{itemize} + \item Todo + \begin{itemize} + \item Try to improve interface + \item Precipitates of different size + \end{itemize} + \end{itemize} +\end{minipage} +} + + \small \end{slide} -- 2.39.2