From ffbb152419ec0697b3e12a77165307a35c056370 Mon Sep 17 00:00:00 2001 From: hackbard Date: Mon, 14 Aug 2006 14:40:16 +0000 Subject: [PATCH] iadded version 2 (mods to obsolete ver1) --- nlsop/poster/nlsop_ibmm2006.tex | 28 ++- nlsop/poster/nlsop_ibmm2006_ver2.tex | 317 +++++++++++++++++++++++++++ 2 files changed, 334 insertions(+), 11 deletions(-) create mode 100644 nlsop/poster/nlsop_ibmm2006_ver2.tex diff --git a/nlsop/poster/nlsop_ibmm2006.tex b/nlsop/poster/nlsop_ibmm2006.tex index 1188e13..0988937 100644 --- a/nlsop/poster/nlsop_ibmm2006.tex +++ b/nlsop/poster/nlsop_ibmm2006.tex @@ -171,7 +171,7 @@ } %\hfill }} -\hfill\mbox{}\\[0.1cm] +\hfill\mbox{}\\[0cm] %\vspace*{1.3cm} @@ -224,10 +224,12 @@ $\rightarrow$ {\bf amourphous} precipitates \item $20 - 30\,\%$ lower silicon density of $a-SiC_x$ compared to $c-Si$\\ $\rightarrow$ {\bf lateral strain} (black arrows) +\item implantation range near surface\\ + $\rightarrow$ {\bf ralaxation} of {\bf vertical strain component} \item reduction of the carbon supersaturation in $c-Si$\\ $\rightarrow$ {\bf carbon diffusion} into amorphous volumina (white arrows) -\item lateral strain (vertical component relaxating)\\ +\item remaining lateral strain\\ $\rightarrow$ {\bf strain induced} lateral amorphization \end{itemize} \end{kasten} @@ -257,9 +259,9 @@ \subsubsection*{3.2.1 Amorphization/Recrystallization} \begin{itemize} - \item random numbers according to the nuclear - energy loss to determine the volume hit - by an impinging ion + \item random numbers distributed according to + the nuclear energy loss to determine the + volume hit by an impinging ion \item compute local probability for amorphization:\\ \[ @@ -289,8 +291,8 @@ Three contributions to the amorphization process controlled by: \subsubsection*{3.2.2 Carbon incorporation} \begin{itemize} - \item random numbers according to the - implantation profile to determine the + \item random numbers distributed according to + the implantation profile to determine the incorporation volume \item increase the amount of carbon atoms in that volume @@ -353,9 +355,10 @@ Three contributions to the amorphization process controlled by: \makebox[11cm]{% \parbox[c]{5cm}{% \begin{itemize} - \item multiple implantation \\ steps + \item multiple implantation\\ + steps \item energies: $180$ - $10 \, keV$ - \item higher temeprature\\ + \item temeprature: $500 ^{\circ} \mathrm{C}$\\ $\rightarrow$ prevent amorphization \end{itemize} $\Rightarrow$ nearly constant carbon distribution @@ -370,14 +373,17 @@ Three contributions to the amorphization process controlled by: \begin{center} \includegraphics[width=10cm]{multiple_impl_e.eps} \end{center} + Starting point for materials with high photoluminescence.\\ + Dihu Chen et al. Opt. Mater. 23 (2003) 65. \end{kasten} \begin{kasten} - \section*{5 \hspace{0.1cm} {\color{red} Conclusions}} + \section*{5 \hspace{0.1cm} {\color{red} Conclusion}} \begin{itemize} \item selforganized nanometric precipitates by ion irradiation \item model describing the seoforganization process - \item precipitate structures traceable by simulation + \item set of parameters reproducing the experimental observations + \item precipitation process traceable by simulation \item detailed structural/compositional information \item recipe for broad distributions of lamellar structure \end{itemize} diff --git a/nlsop/poster/nlsop_ibmm2006_ver2.tex b/nlsop/poster/nlsop_ibmm2006_ver2.tex new file mode 100644 index 0000000..e1ed083 --- /dev/null +++ b/nlsop/poster/nlsop_ibmm2006_ver2.tex @@ -0,0 +1,317 @@ +\documentclass[portrait,a0b,final]{a0poster} +\usepackage{epsf,psfig,pstricks,multicol,pst-grad,color} +\usepackage{graphicx,amsmath,amssymb} +\graphicspath{{../img/}} +\usepackage[german]{babel} + +\begin{document} + +% Fliessenden Hintergrund von RGB-Farbe 1. .98 .98 nach 1. .85 .85 +% und wieder nach 1. .98 .98 (1. .85 .85 wird nach 0.1=10% des Hinter- +% grunds angenommen) +% Achtung Werte unter .8 verbrauchen zu viel Tinte!!! + +%\background{.95 .95 1.}{.78 .78 1.}{0.05} +\background{.50 .50 .50}{.85 .85 .85}{0.5} +%\newrgbcolor{blue1}{.9 .9 1.} + +% Groesse der einzelnen Spalten als Anteil der Gesamt-Textbreite +\renewcommand{\columnfrac}{.31} + +% header +\vspace{-1cm} +\begin{header} + \begin{minipage} {.13\textwidth} + \includegraphics[height=11cm]{uni-logo.eps} + \end{minipage} \hfill + \begin{minipage} {.73\textwidth} + \centerline{{\Huge \bfseries Monte Carlo simulation study of a selforganisation}} + \centerline{{\Huge \bfseries process leading to ordered precipitate structures}} + \vspace*{1cm} + \centerline{\huge\textsc {\underline{F.~Zirkelbach}}, M.~H"aberlen, + J.~K.~N.~Lindner, B.~Stritzker} + \vspace*{1cm} + \centerline{\Large Institut f"ur Physik, Universit"at Augsburg, + D-86135 Augsburg, Germany} + \end{minipage} \hfill + \begin{minipage} {.13\textwidth} + \includegraphics[height=10cm]{Lehrstuhl-Logo.eps} + \end{minipage} \hfill +\end{header} + +\begin{poster} + +\vspace{-1cm} +\begin{pcolumn} + \begin{pbox} + \section*{Motivation} + {\bf + Experimentally observerd seflorganisation process at high-dose carbon + implantations under certain implantation conditions.} + \begin{itemize} + \item Spherical and lamellar amorphous inclusions at the upper + a/c interface + \begin{center} + \includegraphics[width=20cm]{k393abild1_e.eps} + \end{center} + Cross section TEM image:\\ + $180 \, keV$ $C^+ \rightarrow Si$, + $T=150 \, ^{\circ} \mathrm{C}$, + Dose: $4.3 \times 10^{17} \, cm^{-2}$\\ + black/white: crystalline/amorphous material\\ + L: amorphous lamellae, S: spherical amorphous inclusions + \item Carbon accumulation in amorphous volumes + \begin{center} + \includegraphics[width=20cm]{eftem.eps} + \end{center} + Brightfield TEM and respective EFTEM image:\\ + $180 \, keV$ $C^+ \rightarrow Si$, + $T=200 \, ^{\circ} \mathrm{C}$, + Dose: $4.3 \times 10^{17} \, cm^{-2}$\\ + yellow/blue: high/low concentrations of carbon + \end{itemize} + {\bf + Observed for a number of ion/target combinations for which the + material undergoes drastic density change upon amorphisation.}\\ + {\scriptsize + A. H. van Ommen, Nucl. Instr. and Meth. B 39 (1989) 194.\\ + E. D. Specht et al., Nucl. Instr. and Meth. B 84 (1994) 323.\\ + M. Ishimaru et al., Nucl. Instr. and Meth. B 166-167 (2000) 390.} + \end{pbox} + \vspace{-1cm} + \begin{pbox} + \section*{Model} + {\bf + Model schematically displaying the formation of ordered lamellae + with increasing dose.} + \vspace{1cm} + \begin{center} + \includegraphics[width=20cm]{modell_ng_e.eps} + \end{center} + \begin{itemize} +\item supersaturation of $C$ in $c-Si$\\ + $\rightarrow$ {\bf carbon induced} nucleation of spherical + $SiC_x$-precipitates +\item high interfacial energy between $3C-SiC$ and $c-Si$\\ + $\rightarrow$ {\bf amourphous} precipitates +\item $20 - 30\,\%$ lower silicon density of $a-SiC_x$ compared to $c-Si$\\ + $\rightarrow$ {\bf lateral strain} (black arrows) +\item implantation range near surface\\ + $\rightarrow$ {\bf ralaxation} of {\bf vertical strain component} +\item reduction of the carbon supersaturation in $c-Si$\\ + $\rightarrow$ {\bf carbon diffusion} into amorphous volumina + (white arrows) +\item remaining lateral strain\\ + $\rightarrow$ {\bf strain induced} lateral amorphisation + \end{itemize} + \end{pbox} + \vspace{-1cm} + \begin{pbox} + \section*{Simulation} + \begin{minipage}[t]{0.5\textwidth} + {\bf Discretisation of the target} + \begin{center} + \includegraphics[width=12cm]{gitter_e.eps} + \end{center} + \vspace{2cm} + \begin{itemize} + \item divided into cells with a cube length of $3 \, nm$ + \item periodic boundary conditions in $x$,$y$-direction + \end{itemize} + \end{minipage} + \begin{minipage}[t]{0.5\textwidth} + {\bf TRIM collsion statstics} + \begin{center} + \includegraphics[width=12cm]{trim_coll_e.eps} + \end{center} + \begin{itemize} + \item[] $\Rightarrow$ identical depth profiles for + number of + collisions per depth and nuclear stopping power + \item[] $\Rightarrow$ mean constant energy loss per + collision + \end{itemize} + \end{minipage} + \end{pbox} + + +\end{pcolumn} +\begin{pcolumn} + + \begin{pbox} + \section*{Simulation algorithm} + {\bf + The simulation algorithm consists of the following three parts looped + $s$ times corresponding to a dose $D=s/(64\times64\times(3 \, nm)^2)$:} + \subsection*{1. Amorphisation/Recrystallisation} + \begin{itemize} + \item random numbers distributed according to + the nuclear energy loss to determine the + volume in which a collision occurs + \item compute local probability for amorphisation:\\ + %\vspace{0.1cm} + + \centerline{\fcolorbox[rgb]{0.,0.,0.}{1.,1.,.8}{ + \begin{minipage}{20cm} +\[ + p_{c \rightarrow a}(\vec{r}) = {\color{green} p_b} + {\color{blue} p_c c_C(\vec{r})} + {\color{red} \sum_{\textrm{amorphous neighbours}} \frac{p_s c_C(\vec{r'})}{(r-r')^2}} +\] + \end{minipage} + }} + \vspace{1cm} + and recrystallisation:\\ + %\vspace{0.1cm} + + \centerline{\fcolorbox[rgb]{0.,0.,0.}{1.,1.,.8}{ + \begin{minipage}{20cm} +\[ +p_{a \rightarrow c}(\vec r) = (1 - p_{c \rightarrow a}(\vec r)) \Big(1 - \frac{\sum_{direct \, neighbours} \delta (\vec{r'})}{6} \Big) \, \textrm{,} +\] +\[ +\delta (\vec r) = \left\{ +\begin{array}{ll} + 1 & \textrm{if volume at position $\vec r$ is amorphous} \\ + 0 & \textrm{otherwise} \\ +\end{array} +\right. +\] + \end{minipage} + }} + \vspace{1cm} + \item loop for the mean amount of hits by the ion + \end{itemize} + Three contributions to the amorphisation process controlled by: + \begin{itemize} + \item {\color{green} $p_b$} normal 'ballistic' amorphisation + \item {\color{blue} $p_c$} carbon induced amorphisation + \item {\color{red} $p_s$} stress enhanced amorphisation + \end{itemize} + \subsection*{2. Carbon incorporation} + \begin{itemize} + \item random numbers distributed according to + the implantation profile to determine the + incorporation volume + \item increase the amount of carbon atoms in + that volume + \end{itemize} + \subsection*{3. Diffusion/Sputtering} + \begin{itemize} + \item every $d_v$ steps transfer $d_r$ of the + carbon atoms of crystalline volumina to + an amorphous neighbour volume + \item do the sputter routine after $n$ steps + corresponding to $3 \, nm$ of substrat + removal + \end{itemize} + {\bf + Simulation parameters $d_v$, $d_r$ and $n$ control the + diffusion and sputtering process.} + \end{pbox} + \vspace{-1cm} + \begin{pbox} + \section*{Comparison of experiment and simulation} + \begin{center} + \includegraphics[width=25cm]{dosis_entwicklung_ng_e_1-2.eps} + \end{center} + \begin{center} + \includegraphics[width=25cm]{dosis_entwicklung_ng_e_2-2.eps} + \end{center} + Simulation parameters:\\ + $p_b=0.01$, $p_c=0.001$, $p_s=0.0001$, $d_r=0.05$, $d_v=1 \times 10^6$. + \\[0.7cm]{\bf Conclusion:} + \begin{itemize} + \item Essentially conforming formation and growth of the + continuous amorphous layer + \item Lamellar precipitates and their evolution at the upper + a/c interface with increasing dose is reproduced + \end{itemize} + {\bf\color{red} Simulation is able to model the whole + depth region affected by the + irradiation process} + \end{pbox} +\end{pcolumn} +\begin{pcolumn} + + \begin{pbox} + \section*{Structural/compositional information} + \begin{minipage}[t]{0.57\textwidth} + \includegraphics[height=15cm=]{ac_cconc_ver2_e.eps} + \begin{itemize} + \item Fluctuation of the carbon concentration in the + region of the lamellae + \item Saturation limit of carbon in c-$Si$ under given + implantation conditions between $8$ and + $10 \, at. \%$ + \end{itemize} + \end{minipage} + \begin{minipage}[t]{0.43\textwidth} + \includegraphics[height=15cm]{97_98_ng_e.eps} + \begin{itemize} + \item Complementarily arranged and alternating sequence + of layers with high and low amount of amorphous + regions + \item Carbon accumulation in the amorphous phase + \end{itemize} + \end{minipage} + \end{pbox} + \vspace{-1cm} + \begin{pbox} + \section*{Recipe:\\ + Thick films of ordered lamellar structure} + {\bf Prerequisites:}\\ + Crystalline silicon target with a nearly constant carbon + concentration at $10 \, at. \%$ in a $500 \, nm$ thick + surface layer + \begin{center} + \includegraphics[width=18cm]{multiple_impl_cp_e.eps} + \end{center} + {\bf Creation:} + \begin{itemize} + \item multiple energy ($180$-$10 \, keV$) $C^+$ $\rightarrow$ + $Si$ implantation + \item $T=500 \, ^{\circ} \mathrm{C}$, to prevent amorphisation + \end{itemize} + {\bf Stiring up:}\\ + 2nd $2 \, MeV$ $C^+$ $\rightarrow$ $Si$ implantation step at + $150 \, ^{\circ} \mathrm{C}$ + \begin{itemize} + \item This does not significantly change the carbon + concentration in the top $500 \, nm$ + \item Nearly constant energy loss in the affected depth region + \end{itemize} + {\bf Result:} + \begin{center} + \includegraphics[width=25cm]{multiple_impl_e.eps} + \end{center} + \begin{itemize} + \item Already ordered structures after $100 \times 10^6$ steps + corresponding to a dose of $D=2.7 \times 10^{17} cm^{-2}$ + \item More defined structures with increasing dose + \end{itemize} + {\bf\color{blue} Starting point for materials showing strong\\ + photoluminescence}\\ + {\scriptsize Dihu Chen et al. Opt. Mater. 23 (2003) 65.} + \end{pbox} + \vspace{-1cm} + \begin{pbox} + \section*{Conclusions} + \begin{itemize} + \item Observation of self-organised nanometric + precipitates by ion irradiation + \item Model proposed describing the seoforganisation + process + \item Model implemented to a Monte Carlo simulation code + \item Simulation is able to reproduce experimenal + observations + \item Precipitation process gets traceable by simulation + \item Detailed structural/compositional information + available by simulation + \item Recipe proposed for the formation of broad + distributions of lamellar structure + \end{itemize} + \end{pbox} + +\end{pcolumn} +\end{poster} +\end{document} + -- 2.20.1