X-Git-Url: https://hackdaworld.org/gitweb/?a=blobdiff_plain;ds=sidebyside;f=posic%2Ftalks%2Fdpg_2008.tex;h=5bc70e64073c86ab00d93b330646960d123f2bc8;hb=47c75dbe6e5de9b8268c46624ab7e599b2dbd8bb;hp=00e9aafe8e7e867d6cc4501b7c77d6e77a86dbcb;hpb=f1a2d645f3cf375adaca51e26afef0df7adbedeb;p=lectures%2Flatex.git diff --git a/posic/talks/dpg_2008.tex b/posic/talks/dpg_2008.tex index 00e9aaf..5bc70e6 100644 --- a/posic/talks/dpg_2008.tex +++ b/posic/talks/dpg_2008.tex @@ -28,6 +28,8 @@ \articlemag{1} +\special{landscape} + \begin{document} \extraslideheight{10in} @@ -132,8 +134,8 @@ \end{itemize} \item Results gained by simulation \begin{itemize} - \item Carbon interstitials in silicon - \item Existence of $SiC$-precipitates + \item Interstitials in silicon + \item $SiC$-precipitation experiments \end{itemize} \item Conclusion / Outlook \end{itemize} @@ -141,5 +143,185 @@ % start of contents +\begin{slide} + + {\large\bf + Motivation / Introduction + } + + \small + \vspace{6pt} + + Supposed mechanism of the conversion 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} + + \begin{center} + \[5a_{SiC}=4a_{Si} \quad \Rightarrow \quad + \frac{n_{SiC}}{n_{Si}}=\frac{\frac{4}{a_{SiC}^3}}{\frac{8}{a_{Si}^3}}= + \frac{5^3}{2\cdot4^3}=97,66\% + \] + \end{center} + + Experimentally observed minimal diameter of precipitation: 4 - 5 nm + +\end{slide} + +\begin{slide} + + {\large\bf + Simulation details + } + + 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-dimemnsional phase space + \item Observables obtained by time average + \end{itemize} + + \vspace{4pt} + + Application details: + \begin{itemize} + \item Integrator: velocity verlet, timestep: $1\, fs$ + \item Ensemble control: 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 und K. Albe. Phys. Rev. B 71 (2005) 035211} + \end{center} + \end{itemize} + +\end{slide} + +\begin{slide} + + {\large\bf + Simulation details + } + + Interstitial experiments: + \begin{itemize} + \item Initial configuration: $9\times9\times9$ unit cells Si + \item Periodic boundary conditions + \item $T=0 \, K$ + \item Insertion of Si / C atom at + \begin{itemize} + \item $(0,0,0)$ (tetrahedral) + \item $(-1/8,-1/8,1/8)$ (hexagonal) + \item $(-1/8,-1/8,-1/4)$, $(-1/4,-1/4,-1/4)$ (110 dumbbell) + \item random positions (critical distance check) + \end{itemize} + \item Relaxation time: $2\, ps$ + \end{itemize} + +\end{slide} + +\begin{slide} + + {\large\bf + Simulation details + } + + SiC precipitation experiments: + \begin{itemize} + \item Initial configuration: $31\times31\times31$ unit cells Si + \item Periodic boundary conditions + \item $T=450\, ^{\circ}C$ + \item Steady state time: $600\, fs$ + \item C insertion steps: + \begin{itemize} + \item If $T=450\pm 1\, ^{\circ}C$:\\ + Insertion of 10 atoms at random positions within $V_{ins}$ + \item Otherwise: Annealing for another $100\, fs$ + \end{itemize} + \item Annealing: ($T_a: 450\rightarrow 20 \, ^{\circ}C$) + \begin{itemize} + \item If $T=T_a$: Decrease $T_a$ by $1\, ^{\circ}C$ + \item Otherwise: Annealing for another $50\, fs$ + \end{itemize} + \end{itemize} + + 3 szenarios + \begin{itemize} + \item $V_ins$: total volume $V$ + \item $V_ins$: + \end{itemize} + +\end{slide} + +\begin{slide} + + {\large\bf + Results + } + +\end{slide} + +\begin{slide} + + {\large\bf + Results + } + +\end{slide} + +\begin{slide} + + {\large\bf + Results + } + +\end{slide} + +\begin{slide} + + {\large\bf + Results + } + +\end{slide} + +\begin{slide} + + {\large\bf + Conclusion / Outlook + } + +\end{slide} + + \end{document}