X-Git-Url: https://hackdaworld.org/gitweb/?p=lectures%2Flatex.git;a=blobdiff_plain;f=posic%2Ftalks%2Fseminar_2010.tex;h=75ceb623d387c9fb9f95b9e3a3c2025e25f8ea88;hp=b76a6a8b00982686c0eeb47138b09424c9190be7;hb=e08a97849ebaf34c088eef126bf83fa8a4267119;hpb=d38736a6eb059ca733c67a1e454f7734f4d8f338

diff --git a/posic/talks/seminar_2010.tex b/posic/talks/seminar_2010.tex
index b76a6a8..75ceb62 100644
--- a/posic/talks/seminar_2010.tex
+++ b/posic/talks/seminar_2010.tex
@@ -154,14 +154,14 @@
 
 \end{pspicture}
 
-\begin{picture}(0,0)(-10,68)
+\begin{picture}(0,0)(-3,68)
 \includegraphics[width=2.6cm]{wide_band_gap.eps}
 \end{picture}
-\begin{picture}(0,0)(-295,-165)
-\includegraphics[width=3cm]{sic_led.eps}
+\begin{picture}(0,0)(-285,-162)
+\includegraphics[width=3.38cm]{sic_led.eps}
 \end{picture}
-\begin{picture}(0,0)(-215,-165)
-\includegraphics[width=2.5cm]{6h-sic_3c-sic.eps}
+\begin{picture}(0,0)(-195,-162)
+\includegraphics[width=2.8cm]{6h-sic_3c-sic.eps}
 \end{picture}
 \begin{picture}(0,0)(-313,65)
 \includegraphics[width=2.2cm]{infineon_schottky.eps}
@@ -169,6 +169,12 @@
 \begin{picture}(0,0)(-220,65)
 \includegraphics[width=2.9cm]{sic_wechselrichter_ise.eps}
 \end{picture}
+\begin{picture}(0,0)(0,-160)
+\includegraphics[width=3.0cm]{sic_proton.eps}
+\end{picture}
+\begin{picture}(0,0)(-60,65)
+\includegraphics[width=3.4cm]{sic_switch.eps}
+\end{picture}
 
 \end{slide}
 
@@ -314,6 +320,19 @@ 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}
 
@@ -441,8 +460,14 @@ Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\
 \psellipse[linecolor=blue](11.5,5.8)(0.3,0.5)
 \rput{-20}{\psellipse[linecolor=blue](3.3,8.1)(0.3,0.5)}
 \psline[linewidth=4pt]{->}(4.0,2)(4.5,2)
+\rput(12.7,0.3){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
+ $4a_{\text{Si}}=5a_{\text{SiC}}$
+ }}}
+\rput(12.2,8){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
+\hkl(h k l) planes match
+ }}}
 \end{pspicture}
- 
+
 \end{slide}
 
 \begin{slide}
@@ -561,8 +586,10 @@ which in turn depends on $n(r)$
 \[
 \rightarrow
 \text{Fourier series: } \Phi_i=\sum_{|G+k|<G_{\text{cut}}} c_j^i \phi_j(r), \quad E_{\text{cut}}=\frac{\hbar^2}{2m}G^2_{\text{cut}}
+\qquad ({\color{blue}300\text{ eV}})
 \]
-  \item \underline{$k$-point sampling} - $\Gamma$-point only calculations
+  \item \underline{Brillouin zone sampling} -
+        {\color{blue}$\Gamma$-point only} calculations
   \item \underline{Pseudo potential} 
         - consider only the valence electrons
   \item \underline{Code} - VASP 4.6
@@ -578,6 +605,10 @@ which in turn depends on $n(r)$
   \item Structural optimization: Conjugate gradient method
  \end{itemize}
 
+\begin{pspicture}(0,0)(0,0)
+\psellipse[linecolor=blue](1.5,6.75)(0.5,0.3)
+\end{pspicture}
+
 \end{slide}
 
 \begin{slide}
@@ -1971,7 +2002,7 @@ $\Longrightarrow$
 \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}
 }
 
@@ -1993,28 +2024,51 @@ Maximum temperature used: $0.95\cdot T_{\text{m}}$
   Long time scale simulations at maximum temperature
  }
 
- \small
- 
-\vspace{1cm}
+\small
 
+\vspace{0.1cm}
+ 
 \underline{Differences}
 \begin{itemize}
- \item Cubic volume $\Rightarrow$ spherical volume
- \item Amount of C atoms: 6000 $\rightarrow$ 5500
  \item Temperature set to $0.95 \cdot T_{\text{m}}$
+ \item Cubic insertion volume $\Rightarrow$ spherical insertion volume
+ \item Amount of C atoms: 6000 $\rightarrow$ 5500
+       $\Leftrightarrow r_{\text{prec}}=0.3\text{ nm}$
  \item Simulation volume: 21 unit cells of c-Si in each direction
 \end{itemize}
 
-\vspace{1cm}
+\footnotesize
+
+\vspace{0.3cm}
 
+\begin{minipage}[t]{4.5cm}
 \begin{center}
- {\bf
-Simulations in progress! :)\\
- }
-... show evolution of radial distribution in ns timesteps ...
+\underline{Low C concentration, Si-C}
+\includegraphics[width=4.5cm]{c_in_si_95_v1_si-c.ps}\\
+Sharper peaks!
 \end{center}
+\end{minipage}
+\begin{minipage}[t]{4.5cm}
+\begin{center}
+\underline{Low C concentration, C-C}
+\includegraphics[width=4.5cm]{c_in_si_95_v1_c-c.ps}\\
+Sharper peaks!\\
+No C agglomeration!
+\end{center}
+\end{minipage}
+\begin{minipage}[t]{4cm}
+\begin{center}
+\underline{High C concentration}
+\includegraphics[width=4.5cm]{c_in_si_95_v2.ps}\\
+No significant changes
+\end{center}
+\end{minipage}
 
-\vspace{4cm}
+\begin{center}
+\framebox{
+Long time scales and high temperatures most probably not sufficient enough!
+}
+\end{center}
 
 \end{slide}
 
@@ -2060,7 +2114,8 @@ 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}
@@ -2068,7 +2123,7 @@ y=\left(\frac{1}{2} \right)^{1/3}a_{\text{Si}}
 \vspace{0.3cm}
 
 \begin{minipage}{6.2cm}
-\includegraphics[width=6cm,draft=false]{pc_0.ps}
+\includegraphics[width=6cm]{pc_0.ps}
 \end{minipage}
 \begin{minipage}{6.8cm}
 \underline{Results}
@@ -2076,16 +2131,66 @@ 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}
 
@@ -2095,9 +2200,80 @@ y=\left(\frac{1}{2} \right)^{1/3}a_{\text{Si}}
   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}
 
@@ -2107,9 +2283,42 @@ y=\left(\frac{1}{2} \right)^{1/3}a_{\text{Si}}
   Acknowledgements
  }
 
+ \vspace{0.1cm}
+
  \small
 
+ Thanks to \ldots
+
+ \underline{Augsburg}
+ \begin{itemize}
+  \item Prof. B. Stritzker (accepting a simulator at EP \RM{4})
+  \item Ralf Utermann (EDV)
+ \end{itemize}
  
+ \underline{Helsinki}
+ \begin{itemize}
+  \item Prof. K. Nordlund (MD)
+ \end{itemize}
+ 
+ \underline{Munich}
+ \begin{itemize}
+  \item Bayerische Forschungsstiftung (financial support)
+ \end{itemize}
+ 
+ \underline{Paderborn}
+ \begin{itemize}
+  \item Prof. J. Lindner (SiC)
+  \item Prof. G. Schmidt (DFT + financial support)
+  \item Dr. E. Rauls (DFT + SiC)
+ \end{itemize}
+
+\vspace{0.2cm}
+
+\begin{center}
+\framebox{
+\bf Thank you for your attention!
+}
+\end{center}
 
 \end{slide}