1 \documentclass[10pt]{scrartcl}
5 % resize to A0 (900 x 1100 mm) full poster size
9 % 2*sqrt(2) = 2.828 (for A0)
15 % special format, scaled by 2.82 -> A0
42 % ./poster_resize poster.ps S
45 % A3: 29.73 x 42.04 cm
53 \usepackage[latin1]{inputenc}
55 \usepackage{graphicx,psfrag,color,pstricks,pst-grad}
56 \graphicspath{{../img/}}
57 \usepackage{amsmath,amssymb}
61 \usepackage[german]{babel}
63 % numbers, lengths and boxes:
65 \newsavebox{\dummybox}
68 \newlength{\bgwidth}\newlength{\bgheight}
69 \setlength\bgheight{\hoehe} \addtolength\bgheight{-1mm}
70 \setlength\bgwidth{\breite} \addtolength\bgwidth{-1mm}
72 \newlength{\kastenwidth}
74 \setlength\paperheight{\hoehe}
75 \setlength\paperwidth{\breite}
76 \special{papersize=\breite,\hoehe}
84 \setlength{\oddsidemargin}{-2.44cm}
85 \addtolength{\topmargin}{-3mm}
87 \textheight\paperheight
90 \parskip1.5ex plus0.5ex minus 0.5ex
93 \definecolor{recoilcolor}{rgb}{1,0,0}
94 \definecolor{occolor}{rgb}{0,1,0}
95 \definecolor{pink}{rgb}{0,1,1}
97 \def\UberStil{\normalfont\sffamily\bfseries\large}
98 \def\UnterStil{\normalfont\sffamily\small}
99 \def\LabelStil{\normalfont\sffamily\tiny}
100 \def\LegStil{\normalfont\sffamily\tiny}
104 \definecolor{JG}{rgb}{0.1,0.9,0.3}
106 \newenvironment{kasten}{%
107 \begin{lrbox}{\dummybox}%
108 \begin{minipage}{0.96\linewidth}}%
111 \raisebox{-\depth}{\psshadowbox[framesep=1em]{\usebox{\dummybox}}}\\[0.5em]}
113 \newenvironment{spalte}{%
114 \setlength\kastenwidth{1.2\textwidth}
115 \divide\kastenwidth by \anzspalten
116 \begin{minipage}[t]{\kastenwidth}}
117 {\end{minipage}\hfill}
119 \renewcommand{\emph}[1]{{\color{red}\textbf{#1}}}
124 % the document begins ...
129 {\newrgbcolor{gradbegin}{0.1 0.1 0.1}%
130 \newrgbcolor{gradend}{1 1 1}%
131 \psframe[fillstyle=gradient,gradend=gradend,%
132 gradbegin=gradbegin,gradmidpoint=0.5](\bgwidth,-\bgheight)%
138 \psshadowbox{\makebox[0.95\textwidth]{%
140 \parbox[c]{0.1\linewidth}{\includegraphics[height=4.5cm]{uni-logo.eps}}
141 \parbox[c]{0.7\linewidth}{%
143 \textbf{\Huge{Monte Carlo simulation study of a
144 selforganization process\\
145 leading to ordered precipitate structures}
147 \textsc{\LARGE \underline{F. Zirkelbach}, M. H"aberlen,
148 J. K. N. Lindner, B. Stritzker
150 {\large Institut f"ur Physik, Universit"at Augsburg,
151 D-86135 Augsburg, Germany
155 \parbox[c]{0.1\linewidth}{%
156 \includegraphics[height=4.1cm]{Lehrstuhl-Logo.eps}
160 \hfill\mbox{}\\[1.cm]
164 % content, let's rock the columns
165 \begin{lrbox}{\spalten}
166 \parbox[t][\textheight]{1.3\textwidth}{%
173 {\large{\color{blue}\underline{ABSTRACT}}}
175 High-dose ion implantation into solids usually leads to a disordered distribution of defects or precipitates with variable sizes.
176 However materials exist for which high-dose ion irradiation at certain conditions results in periodically arranged, self-organized, nanometric amorphous inclusions.
177 This has been observed for a number of ion/target combinations \cite{ommen,specht,ishimaru} which all have in common a largely reduced density of host atoms of the amorphous phase compared to the crystalline host lattice.
178 A simple model explaining the phenomenon is introduced and realized in a Monte Carlo simulation code, which focuses on high dose carbon implantation into silicon.
179 The simulation is able to reproduce the depth distribution observed by TEM and RBS.
180 While first versions of the simulation \cite{me1,me2} just covered a limited depth region of the target in which the selforganization is observed, the new version of this simulation code presented here is able to model the whole depth region affected by the irradiation process, as can be seen in chapter 4.
181 Based on simulation results a recipe is proposed for producing broad distributions of lamellar, ordered structures which, according to recent studies \cite{wong}, are the starting point for materials with high photoluminescence.
186 \section*{1\hspace{0.1cm}{\color{blue}Experimental observations}}
188 \subsection*{1.1{\color{blue} Amorphous inclusions}}
190 \includegraphics[width=11cm]{k393abild1_e.eps}
192 Cross section TEM image:\\
193 $180 \, keV$ $C^+ \rightarrow Si$,
194 $T=150 \, ^{\circ} \mathrm{C}$,
195 Dose: $4.3 \times 10^{17} \, cm^{-2}$\\
196 black/white: crystalline/amorphous material\\
197 L: amorphous lamellae, S: spherical amorphous inclusions
199 \subsection*{1.2{\color{blue} Carbon distribution}}
201 \includegraphics[width=11cm]{eftem.eps}
203 Brightfield TEM and respective EFTEM image:\\
204 $180 \, keV$ $C^+ \rightarrow Si$,
205 $T=200 \, ^{\circ} \mathrm{C}$,
206 Dose: $4.3 \times 10^{17} \, cm^{-2}$\\
207 yellow/blue: high/low concentrations of carbon
214 \section*{2\hspace{0.1cm}{\color{blue}Model}}
217 \includegraphics[width=11cm]{modell_ng_e.eps}
220 \item supersaturation of $C$ in $c-Si$\\
221 $\rightarrow$ {\bf carbon induced} nucleation of spherical
223 \item high interfacial energy between $3C-SiC$ and $c-Si$\\
224 $\rightarrow$ {\bf amourphous} precipitates
225 \item $20 - 30\,\%$ lower silicon density of $a-SiC_x$ compared to $c-Si$\\
226 $\rightarrow$ {\bf lateral strain} (black arrows)
227 \item reduction of the carbon supersaturation in $c-Si$\\
228 $\rightarrow$ {\bf carbon diffusion} into amorphous volumina
230 \item lateral strain (vertical component relaxating)\\
231 $\rightarrow$ {\bf strain induced} lateral amorphization
236 \section*{3\hspace{0.1cm}{\color{blue}Simulation}}
238 \subsection*{3.1{\color{blue} Discretization of the target}}
240 \includegraphics[width=10cm]{gitter_e.eps}
243 \subsection*{3.2 {\color{blue} Simulation algorithm}}
245 \subsubsection*{3.2.1 Amorphization/Recrystallization}
247 \item random numbers according to the nuclear
248 energy loss to determine the volume hit
250 \item compute local probability for
253 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}}
255 and recrystallization:
257 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{,}
260 \delta (\vec r) = \left\{
262 1 & \textrm{volume at position $\vec r$ amorphous} \\
263 0 & \textrm{otherwise} \\
267 \item loop for the mean amount of hits by the
270 Three contributions to the amorphization process controlled by:
272 \item {\color{green} $p_b$} normal 'ballistic' amorphization
273 \item {\color{blue} $p_c$} carbon induced amorphization
274 \item {\color{red} $p_s$} stress enhanced amorphization
281 \subsubsection*{3.2.2 Carbon incorporation}
283 \item random numbers according to the
284 implantation profile to determine the
286 \item increase the amount of carbon atoms in
289 \subsubsection*{3.2.3 Diffusion/Sputtering}
293 \section*{4 \hspace{0.1cm} {\color{blue}Simulation results}}
303 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
306 \section*{5 \hspace{0.1cm} {\color{red}Fifth Section}}
308 \includegraphics[width=10cm]{blank.ps}
314 \section*{6 \hspace{0.1cm} {\color{red} \underline{Conclusions}}}
331 \begin{thebibliography}{9}
332 \bibitem{ommen} A. H. van Ommen,
333 Nucl. Instr. and Meth. B 39 (1989) 194.
334 \bibitem{specht} E. D. Specht, D. A. Walko, S. J. Zinkle,
335 Nucl. Instr. and Meth. B 84 (2000) 390.
336 \bibitem{ishimaru} M. Ishimaru, R. M. Dickerson, K. E. Sickafus,
337 Nucl. Instr. and Meth. B 166-167 (2000) 390.
338 \bibitem{me1} F. Zirkelbach, M. H"aberlen, J. K. N. Lindner,
340 Comp. Mater. Sci. 33 (2005) 310.
341 \bibitem{me2} F. Zirkelbach, M. H"aberlen, J. K. N. Lindner,
343 Nucl. Instr. and Meth. B 242 (2006) 679.
344 \bibitem{wong} Dihu Chen, Z. M. Liao, L. Wang, H. Z. Wang, Fuli Zhao,
345 W. Y. Cheung, S. P. Wong,
346 Opt. Mater. 23 (2003) 65. Opt. Mater. 23 (2003) 65.
347 \end{thebibliography}
353 \resizebox*{0.98\textwidth}{!}{%
354 \usebox{\spalten}}\hfill\mbox{}\vfill