\usepackage[setpagesize=false]{hyperref}
+% units
+\usepackage{units}
+
\usepackage{semcolor}
\usepackage{semlayer} % Seminar overlays
\usepackage{slidesec} % Seminar sections and list of slides
\newrgbcolor{hlbb}{0.825 0.88 0.968}
\newrgbcolor{lachs}{1.0 .93 .81}
+% shortcuts
+\newcommand{\si}{Si$_{\text{i}}${}}
+\newcommand{\ci}{C$_{\text{i}}${}}
+\newcommand{\cs}{C$_{\text{sub}}${}}
+\newcommand{\degc}[1]{\unit[#1]{$^{\circ}$C}{}}
+\newcommand{\distn}[1]{\unit[#1]{nm}{}}
+\newcommand{\dista}[1]{\unit[#1]{\AA}{}}
+\newcommand{\perc}[1]{\unit[#1]{\%}{}}
+
% topic
\begin{slide}
\vspace{48pt}
-Yet another seminar contribution
+Yet another seminar talk
\vspace{08pt}
- Augsburg am 26. Mai 2011
+ Augsburg, 26. Mai 2011
\end{center}
\end{slide}
\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ Supposed precipitation mechanism of SiC in Si
+ }
+
+ \scriptsize
+
+ \vspace{0.1cm}
+
+ \begin{minipage}{3.8cm}
+ Si \& SiC lattice structure\\[0.2cm]
+ \includegraphics[width=3.5cm]{sic_unit_cell.eps}\\[-0.3cm]
+ \hrule
+ \end{minipage}
+ \hspace{0.6cm}
+ \begin{minipage}{3.8cm}
+ \begin{center}
+ \includegraphics[width=3.3cm]{tem_c-si-db.eps}
+ \end{center}
+ \end{minipage}
+ \hspace{0.6cm}
+ \begin{minipage}{3.8cm}
+ \begin{center}
+ \includegraphics[width=3.3cm]{tem_3c-sic.eps}
+ \end{center}
+ \end{minipage}
+
+ \begin{minipage}{4cm}
+ \begin{center}
+ C-Si dimers (dumbbells)\\[-0.1cm]
+ on Si interstitial sites
+ \end{center}
+ \end{minipage}
+ \hspace{0.2cm}
+ \begin{minipage}{4.2cm}
+ \begin{center}
+ Agglomeration of C-Si dumbbells\\[-0.1cm]
+ $\Rightarrow$ dark contrasts
+ \end{center}
+ \end{minipage}
+ \hspace{0.2cm}
+ \begin{minipage}{4cm}
+ \begin{center}
+ Precipitation of 3C-SiC in Si\\[-0.1cm]
+ $\Rightarrow$ Moir\'e fringes\\[-0.1cm]
+ \& release of Si self-interstitials
+ \end{center}
+ \end{minipage}
+
+ \begin{minipage}{3.8cm}
+ \begin{center}
+ \includegraphics[width=3.3cm]{sic_prec_seq_01.eps}
+ \end{center}
+ \end{minipage}
+ \hspace{0.6cm}
+ \begin{minipage}{3.8cm}
+ \begin{center}
+ \includegraphics[width=3.3cm]{sic_prec_seq_02.eps}
+ \end{center}
+ \end{minipage}
+ \hspace{0.6cm}
+ \begin{minipage}{3.8cm}
+ \begin{center}
+ \includegraphics[width=3.3cm]{sic_prec_seq_03.eps}
+ \end{center}
+ \end{minipage}
+
+\begin{pspicture}(0,0)(0,0)
+\psline[linewidth=4pt]{->}(8.5,2)(9.0,2)
+\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
+ }}}
+\rput(9.7,6.2){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
+r = 2 - 4 nm
+ }}}
+\end{pspicture}
+
+\end{slide}
+
\begin{slide}
{\large\bf
\rput(9.7,6.2){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
r = 2 - 4 nm
}}}
+\rput(6.7,5.2){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white]{
+\begin{minipage}{10cm}
+\small
+{\color{red}\bf Controversial views}
+\begin{itemize}
+\item Implantations at high T (Nejim et al.)
+ \begin{itemize}
+ \item Topotactic transformation based on \cs
+ \item \si{} as supply reacting with further C in cleared volume
+ \end{itemize}
+\item Annealing behavior (Serre et al.)
+ \begin{itemize}
+ \item Room temperature implants $\rightarrow$ highly mobile C
+ \item Elevated T implants $\rightarrow$ no/low C redistribution/migration\\
+ (indicate stable \cs{} configurations)
+ \end{itemize}
+\item Strained silicon \& Si/SiC heterostructures
+ \begin{itemize}
+ \item Coherent SiC precipitates (tensile strain)
+ \item Incoherent SiC (strain relaxation)
+ \end{itemize}
+\end{itemize}
+\end{minipage}
+ }}}
\end{pspicture}
\end{slide}
\vspace*{12pt}
\[
E = \frac{1}{2} \sum_{i \neq j} \pot_{ij}, \quad
- \pot_{ij} = f_C(r_{ij}) \left[ f_R(r_{ij}) + b_{ij} f_A(r_{ij}) \right]
+ \pot_{ij} = {\color{red}f_C(r_{ij})}
+ \left[ f_R(r_{ij}) + {\color{blue}b_{ij}} f_A(r_{ij}) \right]
\]
\end{itemize}
C interstitial point defects in silicon\\[-0.1cm]
}
-\begin{tabular}{l c c c c c c}
+\begin{tabular}{l c c c c c c r}
\hline
- $E_{\text{f}}$ & T & H & \hkl<1 0 0> DB & \hkl<1 1 0> DB & S & B \\
+ $E_{\text{f}}$ & T & H & \hkl<1 0 0> DB & \hkl<1 1 0> DB & S & B & \cs{} \& \si\\
\hline
- VASP & unstable & unstable & \underline{3.72} & 4.16 & 1.95 & 4.66 \\
- Erhart/Albe MD & 6.09 & 9.05$^*$ & \underline{3.88} & 5.18 & 0.75 & 5.59$^*$ \\
+ VASP & unstable & unstable & \underline{3.72} & 4.16 & 1.95 & 4.66 & {\color{green}4.17}\\
+ Erhart/Albe MD & 6.09 & 9.05$^*$ & \underline{3.88} & 5.18 & {\color{red}0.75} & 5.59$^*$ & {\color{green}4.43} \\
\hline
\end{tabular}\\[0.1cm]
\scriptsize
+ \vspace{0.1cm}
+
\begin{minipage}{6.5cm}
\framebox{
-\begin{minipage}{5.9cm}
+\begin{minipage}[t]{5.9cm}
\begin{flushleft}
\includegraphics[width=5.9cm]{bc_00-1.ps}\\[2.35cm]
\end{flushleft}
\item Lowest activation energy: $\approx$ 2.2 eV
\item 2.4 times higher than VASP
\item Different pathway
- \item Transition minima ($\rightarrow$ \hkl<1 1 0> dumbbell)
\end{itemize}
\end{minipage}
\framebox{
\begin{minipage}{5.9cm}
-\begin{flushright}
-\includegraphics[width=5.9cm]{00-1_0-10.ps}\\[0.75cm]
-\end{flushright}
-\begin{center}
-\begin{pspicture}(0,0)(0,0)
-\psframe[linecolor=red,fillstyle=none](-2.8,-0.25)(3.3,1.1)
-\end{pspicture}
-\begin{picture}(0,0)(60,-5)
-\includegraphics[width=0.9cm]{albe_mig/00-1_0-10_red_00.eps}
-\end{picture}
-\begin{picture}(0,0)(0,-5)
-\includegraphics[width=0.9cm]{albe_mig/00-1_0-10_red_min.eps}
-\end{picture}
-\begin{picture}(0,0)(-55,-5)
-\includegraphics[width=0.9cm]{albe_mig/00-1_0-10_red_03.eps}
-\end{picture}
-\begin{picture}(0,0)(12.5,5)
-\includegraphics[width=1cm]{100_arrow.eps}
-\end{picture}
-\begin{picture}(0,0)(90,0)
-\includegraphics[height=0.9cm]{001_arrow.eps}
-\end{picture}
-\end{center}
-\vspace{0.2cm}
+%\begin{flushright}
+%\includegraphics[width=5.9cm]{00-1_0-10.ps}\\[0.75cm]
+%\end{flushright}
+%\begin{center}
+%\begin{pspicture}(0,0)(0,0)
+%\psframe[linecolor=red,fillstyle=none](-2.8,-0.25)(3.3,1.1)
+%\end{pspicture}
+%\begin{picture}(0,0)(60,-5)
+%\includegraphics[width=0.9cm]{albe_mig/00-1_0-10_red_00.eps}
+%\end{picture}
+%\begin{picture}(0,0)(0,-5)
+%\includegraphics[width=0.9cm]{albe_mig/00-1_0-10_red_min.eps}
+%\end{picture}
+%\begin{picture}(0,0)(-55,-5)
+%\includegraphics[width=0.9cm]{albe_mig/00-1_0-10_red_03.eps}
+%\end{picture}
+%\begin{picture}(0,0)(12.5,5)
+%\includegraphics[width=1cm]{100_arrow.eps}
+%\end{picture}
+%\begin{picture}(0,0)(90,0)
+%\includegraphics[height=0.9cm]{001_arrow.eps}
+%\end{picture}
+%\end{center}
+%\vspace{0.2cm}
+%\end{minipage}
+%}\\[0.2cm]
+%
+%\framebox{
+%\begin{minipage}{5.9cm}
+\includegraphics[width=5.9cm]{00-1_110_0-10_mig_albe.ps}
\end{minipage}
-}\\[0.2cm]
+}\\[0.1cm]
-\framebox{
\begin{minipage}{5.9cm}
-\includegraphics[width=5.9cm]{00-1_ip0-10.ps}
+Transition involving \ci{} \hkl<1 1 0>
+\begin{itemize}
+ \item Bond-centered configuration unstable\\
+ $\rightarrow$ \ci{} \hkl<1 1 0> dumbbell
+ \item Transition minima of path 2 \& 3\\
+ $\rightarrow$ \ci{} \hkl<1 1 0> dumbbell
+ \item Activation energy: $\approx$ 2.2 eV \& 0.9 eV
+ \item 2.4 - 3.4 times higher than VASP
+ \item Rotation of dumbbell orientation
+\end{itemize}
+\vspace{0.1cm}
+\begin{center}
+{\color{blue}Overestimated diffusion barrier}
+\end{center}
\end{minipage}
-}
\end{minipage}
\end{minipage}
\begin{minipage}[t]{5.5cm}
\begin{itemize}
- \item Restricted to VASP simulations
- \item $E_{\text{b}}=0$ for isolated non-interacting defects
- \item $E_{\text{b}} \rightarrow 0$ for increasing distance (R)
+ \item $E_{\text{b}}=0$ $\Leftrightarrow$ non-interacting defects\\
+ $E_{\text{b}} \rightarrow 0$ for increasing distance (R)
\item Stress compensation / increase
- \item Most favorable: C clustering
\item Unfavored: antiparallel orientations
\item Indication of energetically favored\\
agglomeration
+ \item Most favorable: C clustering
+ \item However: High barrier ($>4\,\text{eV}$)
+ \item $4\times{\color{cyan}-2.25}$ versus $2\times{\color{orange}-2.39}$
+ (Entropy)
\end{itemize}
\end{minipage}
\includegraphics[width=7cm]{db_along_110_cc.ps}
\end{minipage}
\begin{minipage}{6.0cm}
+\begin{itemize}
+ \item Interaction proportional to reciprocal cube of C-C distance
+ \item Saturation in the immediate vicinity
+ \renewcommand\labelitemi{$\Rightarrow$}
+ \item Agglomeration of \ci{} expected
+ \item Absence of C clustering
+\end{itemize}
\begin{center}
{\color{blue}
- Interaction proportional to reciprocal cube of C-C distance
-}\\[0.2cm]
- Saturation in the immediate vicinity
+ Consisten with initial precipitation model
+}
\end{center}
\end{minipage}
\scriptsize
-\begin{center}
-\begin{minipage}{3.2cm}
-\includegraphics[width=3cm]{sub_110_combo.eps}
-\end{minipage}
-\begin{minipage}{7.8cm}
-\begin{tabular}{l c c c c c c}
-\hline
-C$_{\text{sub}}$ & \hkl<1 1 0> & \hkl<-1 1 0> & \hkl<0 1 1> & \hkl<0 -1 1> &
- \hkl<1 0 1> & \hkl<-1 0 1> \\
-\hline
-1 & \RM{1} & \RM{3} & \RM{3} & \RM{1} & \RM{3} & \RM{1} \\
-2 & \RM{2} & A & A & \RM{2} & C & \RM{5} \\
-3 & \RM{3} & \RM{1} & \RM{3} & \RM{1} & \RM{1} & \RM{3} \\
-4 & \RM{4} & B & D & E & E & D \\
-5 & \RM{5} & C & A & \RM{2} & A & \RM{2} \\
-\hline
-\end{tabular}
-\end{minipage}
-\end{center}
-
-\begin{center}
-\begin{tabular}{l c c c c c c c c c c}
-\hline
-Conf & \RM{1} & \RM{2} & \RM{3} & \RM{4} & \RM{5} & A & B & C & D & E \\
-\hline
-$E_{\text{f}}$ [eV]& 4.37 & 5.26 & 5.57 & 5.37 & 5.12 & 5.10 & 5.32 & 5.28 & 5.39 & 5.32 \\
-$E_{\text{b}}$ [eV] & -0.97 & -0.08 & 0.22 & -0.02 & -0.23 & -0.25 & -0.02 & -0.06 & 0.05 & -0.03 \\
-$r$ [nm] & 0.292 & 0.394 & 0.241 & 0.453 & 0.407 & 0.408 & 0.452 & 0.392 & 0.456 & 0.453\\
-\hline
-\end{tabular}
-\end{center}
+%\begin{center}
+%\begin{minipage}{3.2cm}
+%\includegraphics[width=3cm]{sub_110_combo.eps}
+%\end{minipage}
+%\begin{minipage}{7.8cm}
+%\begin{tabular}{l c c c c c c}
+%\hline
+%C$_{\text{sub}}$ & \hkl<1 1 0> & \hkl<-1 1 0> & \hkl<0 1 1> & \hkl<0 -1 1> &
+% \hkl<1 0 1> & \hkl<-1 0 1> \\
+%\hline
+%1 & \RM{1} & \RM{3} & \RM{3} & \RM{1} & \RM{3} & \RM{1} \\
+%2 & \RM{2} & A & A & \RM{2} & C & \RM{5} \\
+%3 & \RM{3} & \RM{1} & \RM{3} & \RM{1} & \RM{1} & \RM{3} \\
+%4 & \RM{4} & B & D & E & E & D \\
+%5 & \RM{5} & C & A & \RM{2} & A & \RM{2} \\
+%\hline
+%\end{tabular}
+%\end{minipage}
+%\end{center}
+
+%\begin{center}
+%\begin{tabular}{l c c c c c c c c c c}
+%\hline
+%Conf & \RM{1} & \RM{2} & \RM{3} & \RM{4} & \RM{5} & A & B & C & D & E \\
+%\hline
+%$E_{\text{f}}$ [eV]& 4.37 & 5.26 & 5.57 & 5.37 & 5.12 & 5.10 & 5.32 & 5.28 & 5.39 & 5.32 \\
+%$E_{\text{b}}$ [eV] & -0.97 & -0.08 & 0.22 & -0.02 & -0.23 & -0.25 & -0.02 & -0.06 & 0.05 & -0.03 \\
+%$r$ [nm] & 0.292 & 0.394 & 0.241 & 0.453 & 0.407 & 0.408 & 0.452 & 0.392 & 0.456 & 0.453\\
+%\hline
+%\end{tabular}
+%\end{center}
\begin{minipage}{6.0cm}
\includegraphics[width=5.8cm]{c_sub_si110.ps}
\end{minipage}
\begin{minipage}{7cm}
-\small
+\scriptsize
\begin{itemize}
\item IBS: C may displace Si\\
$\Rightarrow$ C$_{\text{sub}}$ + \hkl<1 1 0> Si self-interstitial
\item Assumption:\\
\hkl<1 1 0>-type $\rightarrow$ favored combination
\renewcommand\labelitemi{$\Rightarrow$}
- \item Less favorable than C-Si \hkl<1 0 0> dumbbell\\
- ($E_{\text{f}}=3.88\text{ eV}$)
+ \item Most favorable: \cs{} along \hkl<1 1 0> chain \si{}
+ \item Less favorable than C-Si \hkl<1 0 0> dumbbell
\item Interaction drops quickly to zero\\
- (low interaction capture radius)
+ $\rightarrow$ low capture radius
+\end{itemize}
+\begin{center}
+ {\color{blue}
+ IBS process far from equilibrium\\
+ \cs{} \& \si{} instead of thermodynamic ground state
+ }
+\end{center}
+\end{minipage}
+
+\begin{minipage}{6.5cm}
+\includegraphics[width=6.0cm]{162-097.ps}
+\begin{itemize}
+ \item Low migration barrier
\end{itemize}
\end{minipage}
+\begin{minipage}{6.5cm}
+\begin{center}
+Ab initio MD at \degc{900}\\
+\includegraphics[width=3.3cm]{md_vasp_01.eps}
+$t=\unit[2230]{fs}$\\
+\includegraphics[width=3.3cm]{md_vasp_02.eps}
+$t=\unit[2900]{fs}$
+\end{center}
+{\color{blue}
+Contribution of entropy to structural formation
+}
+\end{minipage}
\end{slide}
Conclusion of defect / migration / combined defect simulations
}
- \small
+ \footnotesize
\vspace*{0.1cm}
\begin{itemize}
\item Accurately described by quantum-mechanical simulations
\item Less accurate description by classical potential simulations
+ \item Underestimated formation energy of \cs{} by classical approach
+ \item Both methods predict same ground state: \ci{} \hkl<1 0 0> dumbbell
\end{itemize}
-\vspace*{0.2cm}
+
+Migration
\begin{itemize}
- \item \hkl<1 0 0> C-Si dumbbell interstitial ground state configuration
- \item Consistent with reorientation and diffusion experiments
\item C migration pathway in Si identified
+ \item Consistent with reorientation and diffusion experiments
+\end{itemize}
+\begin{itemize}
+ \item Different path and ...
+ \item overestimated barrier by classical potential calculations
\end{itemize}
Concerning the precipitation mechanism
\begin{itemize}
\item Agglomeration of C-Si dumbbells energetically favorable
+ (stress compensation)
\item C-Si indeed favored compared to
C$_{\text{sub}}$ \& \hkl<1 1 0> Si self-interstitial
\item Possible low interaction capture radius of
C$_{\text{sub}}$ \& \hkl<1 1 0> Si self-interstitial
+ \item Low barrier for
+ \ci{} \hkl<1 0 0> $\rightarrow$ \cs{} \& \si{} \hkl<1 1 0>
\item In absence of nearby \hkl<1 1 0> Si self-interstitial:
C-Si \hkl<1 0 0> + Vacancy $\rightarrow$ C$_{\text{sub}}$ (SiC)
\end{itemize}
\begin{center}
-{\color{blue}Some results point to a different precipitation mechanism!}
+{\color{blue}Results suggest increased participation of \cs}
\end{center}
-In progress ...
-\begin{itemize}
- \item \hkl<1 0 0> C-Si $\rightarrow$
- C$_{\text{sub}}$ \& \hkl<1 1 0> Si self-interstitial
- \item \hkl<1 0 0> C-Si combinations: C-C $\rightarrow$ C-...-C
-\end{itemize}
-
\end{slide}
\end{slide}
+\begin{slide}
+
+ {\large\bf\boldmath
+ Silicon carbide precipitation simulations at $450\,^{\circ}\mathrm{C}$ as in IBS
+ }
+
+ \small
+
+\begin{minipage}{6.5cm}
+\includegraphics[width=6.4cm]{sic_prec_450_si-si_c-c.ps}
+\end{minipage}
+\begin{minipage}{6.5cm}
+\includegraphics[width=6.4cm]{sic_prec_450_energy.ps}
+\end{minipage}
+
+\begin{minipage}{6.5cm}
+\includegraphics[width=6.4cm]{sic_prec_450_si-c.ps}
+\end{minipage}
+\begin{minipage}{6.5cm}
+\scriptsize
+\underline{Low C concentration ($V_1$)}\\
+\hkl<1 0 0> C-Si dumbbell dominated structure
+\begin{itemize}
+ \item Si-C bumbs around 0.19 nm
+ \item C-C peak at 0.31 nm (as expected in 3C-SiC):\\
+ concatenated dumbbells of various orientation
+ \item Si-Si NN distance stretched to 0.3 nm
+\end{itemize}
+{\color{blue}$\Rightarrow$ C atoms in proper 3C-SiC distance first}\\
+\underline{High C concentration ($V_2$, $V_3$)}\\
+High amount of strongly bound C-C bonds\\
+Defect density $\uparrow$ $\Rightarrow$ considerable amount of damage\\
+Only short range order observable\\
+{\color{blue}$\Rightarrow$ amorphous SiC-like phase}
+\end{minipage}
+
+\begin{pspicture}(0,0)(0,0)
+\rput(6.7,5.2){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white]{
+\begin{minipage}{10cm}
+\small
+{\color{red}\bf 3C-SiC formation fails to appear}
+\begin{itemize}
+\item Low C concentration simulations
+ \begin{itemize}
+ \item Formation of \ci{} indeed occurs
+ \item Agllomeration not observed
+ \end{itemize}
+\item High C concentration simulations
+ \begin{itemize}
+ \item Amorphous SiC-like structure\\
+ (not expected at prevailing temperatures)
+ \item Rearrangement and transition into 3C-SiC structure missing
+ \end{itemize}
+\end{itemize}
+\end{minipage}
+ }}}
+\end{pspicture}
+
+\end{slide}
+
\begin{slide}
{\large\bf
\end{slide}
+\begin{slide}
+
+ {\large\bf
+ Increased temperature simulations at low C concentration
+ }
+
+\small
+
+\begin{minipage}{6.5cm}
+\includegraphics[width=6.4cm]{tot_pc_thesis.ps}
+\end{minipage}
+\begin{minipage}{6.5cm}
+\includegraphics[width=6.4cm]{tot_pc3_thesis.ps}
+\end{minipage}
+
+\begin{minipage}{6.5cm}
+\includegraphics[width=6.4cm]{tot_pc2_thesis.ps}
+\end{minipage}
+\begin{minipage}{6.5cm}
+\scriptsize
+ \underline{Si-C bonds:}
+ \begin{itemize}
+ \item Vanishing cut-off artifact (above $1650\,^{\circ}\mathrm{C}$)
+ \item Structural change: C-Si \hkl<1 0 0> $\rightarrow$ C$_{\text{sub}}$
+ \end{itemize}
+ \underline{Si-Si bonds:}
+ {\color{blue}Si-C$_{\text{sub}}$-Si} along \hkl<1 1 0>
+ ($\rightarrow$ 0.325 nm)\\[0.1cm]
+ \underline{C-C bonds:}
+ \begin{itemize}
+ \item C-C next neighbour pairs reduced (mandatory)
+ \item Peak at 0.3 nm slightly shifted
+ \begin{itemize}
+ \item C-Si \hkl<1 0 0> combinations (dashed arrows)\\
+ $\rightarrow$ C-Si \hkl<1 0 0> \& C$_{\text{sub}}$
+ combinations (|)\\
+ $\rightarrow$ pure {\color{blue}C$_{\text{sub}}$ combinations}
+ ($\downarrow$)
+ \item Range [|-$\downarrow$]:
+ {\color{blue}C$_{\text{sub}}$ \& C$_{\text{sub}}$
+ with nearby Si$_{\text{I}}$}
+ \end{itemize}
+ \end{itemize}
+\end{minipage}
+
+%\begin{picture}(0,0)(-330,-74)
+%\color{blue}
+%\framebox{
+%\begin{minipage}{1.6cm}
+%\tiny
+%\begin{center}
+%stretched SiC\\[-0.1cm]
+%in c-Si
+%\end{center}
+%\end{minipage}
+%}
+%\end{picture}
+
+\begin{pspicture}(0,0)(0,0)
+\rput(6.7,5.2){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white]{
+\begin{minipage}{10cm}
+\small
+{\color{blue}\bf Stretched SiC in c-Si}
+\begin{itemize}
+\item Consistent to precipitation model involving \cs{}
+\item Explains annealing behavior of high/low T C implants
+ \begin{itemize}
+ \item Low T: highly mobiel \ci{}
+ \item High T: stable configurations of \cs{}
+ \end{itemize}
+\end{itemize}
+$\Rightarrow$ High T $\leftrightarrow$ IBS conditions far from equilibrium\\
+$\Rightarrow$ Precipitation mechanism involving \cs{}
+\end{minipage}
+ }}}
+\end{pspicture}
+
+\end{slide}
+
\begin{slide}
{\large\bf
\includegraphics[width=6.4cm]{12_pc_c_thesis.ps}
\end{minipage}
-\begin{center}
-Decreasing cut-off artifact\\
-High amount of {\color{red}damage} \& alignement to c-Si host matrix lost
-$\Rightarrow$ hard to categorize
-\end{center}
-
\vspace{0.1cm}
+\scriptsize
+
\framebox{
\begin{minipage}[t]{6.0cm}
0.186 nm: Si-C pairs $\uparrow$\\
\end{minipage}
}
-\vspace{0.1cm}
-
-\begin{center}
-{\color{red}Amorphous} SiC-like phase remains\\
-Slightly sharper peaks
-$\Rightarrow$ indicate slight {\color{blue}acceleration of dynamics}
-due to temperature\\[0.1cm]
-\framebox{
-\bf
-Continue with higher temperatures and longer time scales
-}
-\end{center}
-
-\end{slide}
-
-\begin{slide}
-
- {\large\bf
- Long time scale simulations at maximum temperature
- }
-
-\small
-
-\vspace{0.1cm}
-
-\underline{Differences}
\begin{itemize}
- \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
+\item Decreasing cut-off artifact
+\item {\color{red}Amorphous} SiC-like phase remains
+\item High amount of {\color{red}damage} \& alignement to c-Si host matrix lost
+\item Slightly sharper peaks $\Rightarrow$ indicate slight {\color{blue}acceleration of dynamics} due to temperature
\end{itemize}
-\footnotesize
-
-\vspace{0.3cm}
-
-\begin{minipage}[t]{4.5cm}
-\begin{center}
-\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\\
-C-Si-Si $\uparrow$\\
-C-Si-C $\downarrow$
-\end{center}
-\end{minipage}
+\vspace{-0.1cm}
\begin{center}
+{\color{blue}
\framebox{
-Long time scales and high temperatures most probably not sufficient enough!
+{\color{black}
+High C \& small $V$ \& short $t$
+$\Rightarrow$
+}
+Slow restructuring due to strong C-C bonds
+{\color{black}
+$\Leftarrow$
+High C \& low T implants
+}
+}
}
\end{center}
\begin{slide}
{\large\bf
- Summary / Conclusion / Outlook
+ Summary and Conclusions
}
\scriptsize
-\vspace{0.1cm}
+%\vspace{0.1cm}
\framebox{
-\begin{minipage}{12.9cm}
- \underline{Defects}
+\begin{minipage}[t]{12.9cm}
+ \underline{Pecipitation simulations}
\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 In progress
- \begin{itemize}
- \item Migrations separating C-C bond in \hkl<1 0 0> C-Si dumbbell
- interstitial combination
- \item Migration: \hkl<1 0 0> C-Si $\rightarrow$
- C$_{\text{sub}}$ \& Si \hkl<1 1 0> interstitial
- \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}
+ \item High C concentration $\rightarrow$ amorphous SiC like phase
+ \item Problem of potential enhanced slow phase space propagation
+ \item Low T $\rightarrow$ C-Si \hkl<1 0 0> dumbbell dominated structure
+ \item High T $\rightarrow$ C$_{\text{sub}}$ dominated structure
+ \item High T necessary to simulate IBS conditions (far from equilibrium)
+ \item Precipitation by successive agglomeration of \cs (epitaxy)
+ \item \si{}: vehicle to form \cs{} \& supply of Si \& stress compensation
+ (stretched SiC, interface)
\end{itemize}
\end{minipage}
}
-\vspace{0.2cm}
+%\vspace{0.1cm}
\framebox{
-\begin{minipage}[t]{12.9cm}
- \underline{Pecipitation simulations}
+\begin{minipage}{12.9cm}
+ \underline{Defects}
\begin{itemize}
- \item Summary \& conclusion
+ \item DFT / EA
\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
+ \item Point defects excellently / fairly well described
+ by DFT / EA
+ \item C$_{\text{sub}}$ drastically underestimated by EA
+ \item EA predicts correct ground state:
+ C$_{\text{sub}}$ \& \si{} $>$ \ci{}
+ \item Identified migration path explaining
+ diffusion and reorientation experiments by DFT
+ \item EA fails to describe \ci{} migration:
+ Wrong path \& overestimated barrier
\end{itemize}
- \item Todo
- \begin{itemize}
- \item Accelerated method: self-guided MD
- \item Activation relaxation technique
- \item Constrainted transition path
+ \item Combinations of defects
+ \begin{itemize}
+ \item Agglomeration of point defects energetically favorable
+ by compensation of stress
+ \item Formation of C-C unlikely
+ \item C$_{\text{sub}}$ favored conditions (conceivable in IBS)
+ \item \ci{} \hkl<1 0 0> $\leftrightarrow$ \cs{} \& \si{} \hkl<1 1 0>\\
+ Low barrier (\unit[0.77]{eV}) \& low capture radius
\end{itemize}
\end{itemize}
\end{minipage}
}
- \small
+\begin{center}
+{\color{blue}
+\framebox{Precipitation by successive agglomeration of \cs{}}
+}
+\end{center}
\end{slide}
\underline{Augsburg}
\begin{itemize}
- \item Prof. B. Stritzker (accepting a simulator at EP \RM{4})
+ \item Prof. B. Stritzker (accomodation at EP \RM{4})
\item Ralf Utermann (EDV)
\end{itemize}
projects / lectures / latex.git / blobdiff