Die Alternative: Ionenstrahlsynthese
+ {\small
+
\begin{itemize}
\item Implantation 1:
- 180 keV C$^+\rightarrow$ FZ-Si(100), $D=7.9 \times 10^{17}$ cm$^{-2}$,
+ 180 keV C$^+\rightarrow$ FZ-Si(100),
+ $D=7.9 \times 10^{17}$ cm$^{-2}$,
$T_{\text{i}}=500 \, ^{\circ} \text{C}$\\
- $\rightarrow$
+ epitaktisch orientierte 3C-SiC Ausscheidungen
+ in kastenf"ormigen Bereich,\\
+ eingeschlossen in a-Si:C
\item Implantation 2:
- 180 keV C$^+\rightarrow$ FZ-Si(100), $D=0.6 \times 10^{17}$ cm$^{-2}$,
+ 180 keV C$^+\rightarrow$ FZ-Si(100),
+ $D=0.6 \times 10^{17}$ cm$^{-2}$,
$T_{\text{i}}=250 \, ^{\circ} \text{C}$\\
- $\rightarrow$
+ Zerst"orung einzelner SiC Ausscheidungen
+ in gr"o"ser werdenden amorphen Grenzschichten
\item Tempern:
- $T=1250 \, ^{\circ} \text{C}$, $t=10\text{ h}$
+ $T=1250 \, ^{\circ} \text{C}$, $t=10\text{ h}$\\
+ Homogene st"ochiometrische 3C-SiC Schicht mit
+ scharfen Grenzfl"achen
\end{itemize}
+
+ \begin{minipage}{6.3cm}
+ \includegraphics[width=6.3cm]{ibs_3c-sic.eps}
+ \end{minipage}
+ \hspace*{0.2cm}
+ \begin{minipage}{6.5cm}
+ \vspace*{2.3cm}
+ {\scriptsize
+ Querschnitts-TEM-Aufnahme einer einkristallinen vergrabenen
+ 3C-SiC-Schicht.\\
+ (a) Hellfeldaufnahme\\
+ (b) 3C-SiC(111) Dunkelfeldaufnahme\\
+ }
+ \end{minipage}
+
+ \vspace{0.2cm}
+
+ Entscheidende Parameter: Dosis und Implantationstemperatur
+
+}
\end{slide}
SiC-Ausscheidungsvorgang
}
- \vspace{64pt}
+ Hochaufl"osungs-TEM:\\[-0.5cm]
- Hier die aus experimentellen Untersuchungen heraus vermuteten
- Ausscheidungsvorgaenge rein.
+ \begin{minipage}{3.3cm}
+ \includegraphics[width=3.3cm]{tem_c-si-db.eps}
+ \end{minipage}
+ \begin{minipage}{9cm}
+ Bereich oberhalb des Implantationsmaximums\\
+ Wolkenstruktur "uberlagert auf ungest"orten Si-Muster\\
+ $\rightarrow$ C-Si Dumbbells
+ \end{minipage}
+ \begin{minipage}{3.3cm}
+ \includegraphics[width=3.3cm]{tem_3c-sic.eps}
+ \end{minipage}
+ \begin{minipage}{9cm}
+ Bereich ums Implantationsmaximum\\
+ Moir\'e-Kontrast-Muster\\
+ $\rightarrow$ inkoh"arente 3C-SiC-Ausscheidungen in c-Si-Matrix
+ \end{minipage}
\end{slide}
\small
- \begin{minipage}{4cm}
+ \begin{minipage}{5.5cm}
\begin{itemize}
\item $E_f=0.47$ eV
- \item Very often observed
- \item Most energetically\\
- favorable configuration
- \item Experimental\\
- evidence [6]
+ \item sehr h"aufig beobachtet
+ \item energetisch g"unstigste\\ Konfiguration
+ \item experimentelle und theoretische Hinweise
+ f"ur die Existenz dieser Konfiguration
\end{itemize}
- \vspace{24pt}
- {\tiny
- [6] G. D. Watkins and K. L. Brower,\\
- Phys. Rev. Lett. 36 (1976) 1329.
- }
+ \includegraphics[width=5.6cm]{c_in_si_100.ps}
\end{minipage}
- \begin{minipage}{8cm}
- \includegraphics[width=9cm]{100-c-si-db_s.eps}
+ \begin{minipage}{7cm}
+ \includegraphics[width=8cm]{100-c-si-db_s.eps}
\end{minipage}
\end{slide}
\end{itemize}
}}}}
\rput(3.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=lbb]{
- \parbox{3.5cm}{
- Abk"uhlen auf $20\, ^{\circ}\textrm{C}$
+ \parbox{5.0cm}{
+ Nach 100 ps abk"uhlen auf $20\, ^{\circ}\textrm{C}$
}}}}
\ncline[]{->}{init}{insert}
\ncline[]{->}{insert}{cool}
\end{slide}
-\end{document}
-
\begin{slide}
{\large\bf
\includegraphics[width=6.3cm]{pc_si-c_c-c.eps}
\includegraphics[width=6.3cm]{pc_si-si.eps}
- \begin{minipage}[t]{6.3cm}
- \tiny
- \begin{itemize}
- \item C-C peak at 0.15 nm similar to next neighbour distance of graphite
- or diamond\\
- $\Rightarrow$ Formation of strong C-C bonds
- (almost only for high C concentrations)
- \item Si-C peak at 0.19 nm similar to next neighbour distance in 3C-SiC
- \item C-C peak at 0.31 nm equals C-C distance in 3C-SiC\\
- (due to concatenated, differently oriented
- <100> dumbbell interstitials)
- \item Si-Si shows non-zero g(r) values around 0.31 nm like in 3C-SiC\\
- and a decrease at regular distances\\
- (no clear peak,
- interval of enhanced g(r) corresponds to C-C peak width)
- \end{itemize}
- \end{minipage}
- \begin{minipage}[t]{6.3cm}
- \tiny
- \begin{itemize}
- \item Low C concentration (i.e. $V_1$):
- The <100> dumbbell configuration
- \begin{itemize}
- \item is identified to stretch the Si-Si next neighbour distance
- to 0.3 nm
- \item is identified to contribute to the Si-C peak at 0.19 nm
- \item explains further C-Si peaks (dashed vertical lines)
- \end{itemize}
- $\Rightarrow$ C atoms are first elements arranged at distances
- expected for 3C-SiC\\
- $\Rightarrow$ C atoms pull the Si atoms into the right
- configuration at a later stage
- \item High C concentration (i.e. $V_2$ and $V_3$):
- \begin{itemize}
- \item High amount of damage introduced into the system
- \item Short range order observed but almost no long range order
- \end{itemize}
- $\Rightarrow$ Start of amorphous SiC-like phase formation\\
- $\Rightarrow$ Higher temperatures required for proper SiC formation
- \end{itemize}
- \end{minipage}
+ \vspace{-0.1cm}
+
+ \footnotesize
+ \underline{C-C, 0.15 nm}:\\
+ NN-Abstand in Graphit/Diamant\\
+ $\Rightarrow$ starke C-C Bindungen bei hohen Konz.\\
+ \underline{Si-C, 0.19 nm}:\\
+ NN-Abstand in 3C-SiC\\
+ \underline{C-C, 0.31 nm}:\\
+ C-C Abstand in 3C-SiC\\
+ vekettete, verschieden orientierte 100 C-Si DBs\\
+ \underline{Si-Si, $\sim$ 0.31 nm}:\\
+ g(r) erh"oht, Si-Si in 3C-SiC\\
+ Intervall entspricht C-C Peakbreite\\
+ Abfall bei regul"aren Abst"anden
+
+ \begin{picture}(0,0)(-175,-40)
+ \includegraphics[width=4.0cm]{conc_100_c-si-db_02.eps}
+ \end{picture}
+ \begin{picture}(0,0)(-278,-10)
+ \includegraphics[width=4.0cm]{conc_100_c-si-db_01.eps}
+ \end{picture}
+
+ \end{slide}
+
+ \begin{slide}
+
+ {\large\bf
+ Simulationen zum Ausscheidungsvorgang
+ }
+
+ \includegraphics[width=6.3cm]{pc_si-c_c-c.eps}
+ \includegraphics[width=6.3cm]{c_in_si_100.ps}
+
+ \footnotesize
+
+ \underline{Niedrige C-Konzentration ($V_1$)}:
+ 100 Dumbbell-Konfiguration
+ \begin{itemize}
+ \item dehnt Si-Si NN-Abstand auf 0.3 nm
+ \item Beitrag zum Si-C Peak bei 0.19 nm
+ \item erkl"art weitere Si-C Peaks (gestrichelte Linien)
+ \end{itemize}
+ $\Rightarrow$ C-Atome als erstes im erwarteten 3C-SiC-Abstand
+ \underline{Hohe C-Konzentration ($V_2$ und $V_3$)}:
+ \begin{itemize}
+ \item High amount of damage introduced into the system
+ \item Short range order observed but almost no long range order
+ \end{itemize}
+ $\Rightarrow$ Start of amorphous SiC-like phase formation\\
+ $\Rightarrow$ Higher temperatures required for proper SiC formation
\end{slide}