\documentclass[landscape,semhelv]{seminar}
\usepackage{verbatim}
-\usepackage[german]{babel}
+\usepackage[greek,german]{babel}
\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
%\renewcommand{\familydefault}{\sfdefault}
%\usepackage{mathptmx}
+\usepackage{upgreek}
+
\begin{document}
\extraslideheight{10in}
\vspace{08pt}
- 13. November 2008
+ 20. November 2008
\end{center}
\end{slide}
\item hohe mechanische Stabilit"at
\item gute Ladungstr"agermobilit"at
\item sp"ate S"attigung der Elektronen-Driftgeschwindigkeit
+ \item hohe Durchbruchfeldst"arke
\item chemisch inerte Substanz
\item hohe thermische Leitf"ahigkeit und Stabilit"at
\item geringer Neutroneneinfangquerschnitt
Anwendungen:
\begin{itemize}
- \item Hochfrequenz-, Hochtemperatur und Hochleistungsbauelemente
- \item blaue LEDs
+ \item Hochfrequenz-, Hochtemperatur- und Hochleistungsbauelemente
+ \item Optoelektronik (blaue LEDs), Sensoren
\item Kandidat f"ur Tr"ager und W"ande in Fusionsreaktoren
- \item Luft- und Raumfahrtindistrie, Milit"ar
+ \item Luft- und Raumfahrtindustrie, Milit"ar
\item kohlenfaserverst"arkte SiC-Verbundkeramik
\end{itemize}
}
- \begin{picture}(0,0)(-275,-150)
- \includegraphics[width=4cm]{sic_inverter_ise.eps}
+ \begin{picture}(0,0)(-280,-150)
+ %\includegraphics[width=4cm]{sic_inverter_ise.eps}
\end{picture}
- \begin{picture}(0,0)(-275,-20)
- \includegraphics[width=4cm]{cc_sic_brake_dlr.eps}
+ \begin{picture}(0,0)(-280,-20)
+ %\includegraphics[width=4cm]{cc_sic_brake_dlr.eps}
\end{picture}
\end{slide}
{\large\bf
Motivation
}
+
+ \vspace{4pt}
+
+ SiC - \emph{Born from the stars, perfected on earth.}
- Problem:
+ \vspace{4pt}
- However, in order to become economically viable, several critical materials and processing issues still need to be solved. The most serious issue is the immature state of the crystal growth technology, where increases in wafer size and quality are urgently needed.
+ Herstellung d"unner SiC-Filme:
+ \begin{itemize}
+ \item modifizierter Lely-Prozess
+ \begin{itemize}
+ \item Impfkristall mit $T=2200 \, ^{\circ} \text{C}$
+ \item umgeben von polykristallinen SiC mit
+ $T=2400 \, ^{\circ} \text{C}$
+ \end{itemize}
+ \item CVD Homoepitaxie
+ \begin{itemize}
+ \item 'step controlled epitaxy' auf 6H-SiC-Substrat
+ \item C$_3$H$_8$/SiH$_4$/H$_2$ bei $1500 \, ^{\circ} \text{C}$
+ \item Winkel $\rightarrow$ 3C/6H/4H-SiC
+ \item hohe Qualit"at aber limitiert durch\\
+ Substratgr"o"se
+ \end{itemize}
+ \item CVD/MBE Heteroepitaxie von 3C-SiC auf Si
+ \begin{itemize}
+ \item 2 Schritte: Karbonisierung und Wachstum
+ \item $T=650-1050 \, ^{\circ} \text{C}$
+ \item Qualit"at/Gr"o"se noch nicht ausreichend
+ \end{itemize}
+ \end{itemize}
- Und andersrum:
+ \begin{picture}(0,0)(-245,-50)
+ \includegraphics[width=5cm]{6h-sic_3c-sic.eps}
+ \end{picture}
+ \begin{picture}(0,0)(-240,-35)
+ \begin{minipage}{5cm}
+ {\scriptsize
+ NASA: 6H-SiC LED und 3C-SiC LED\\[-6pt]
+ nebeneinander auf 6H-SiC-Substrat
+ }
+ \end{minipage}
+ \end{picture}
- Modifikation der Bandl"ucke und Spannungen in Heterostrukturen
+\end{slide}
- Kein SiC-Ausscheidungsvorgang erw"unscht!
+\begin{slide}
- {\tiny
- [1] J. H. Edgar, J. Mater. Res. 7 (1992) 235.}\\
- {\tiny
- [2] J. W. Strane, S. R. Lee, H. J. Stein, S. T. Picraux,
- J. K. Watanabe, J. W. Mayer, J. Appl. Phys. 79 (1996) 637.}
+ {\large\bf
+ Motivation
+ }
+ \vspace{8pt}
+
+ 3C-SiC (\foreignlanguage{greek}{b}-SiC) /
+ 6H-SiC (\foreignlanguage{greek}{a}-SiC)
+ \begin{itemize}
+ \item h"ohere Ladungstr"agerbeweglichkeit in \foreignlanguage{greek}{b}-SiC
+ \item h"ohere Durchbruchfeldst"arke in \foreignlanguage{greek}{b}-SiC
+ \item Micropipes (makroskopischer Bereich an Fehlstellen bis hin zur
+ Oberfl"ache) entlang c-Richtung
+ bei \foreignlanguage{greek}{a}-SiC
+ \item gro"sfl"achige epitaktische \foreignlanguage{greek}{a}-SiC-Herstellung
+ sehr viel weiter fortgeschritten verglichen mit der von 3C-SiC
+ \end{itemize}
+
+ \vspace{16pt}
+
+ {\color{blue}
+ \begin{center}
+ Genaues Verst"andnis des 3C-SiC-Ausscheidungsvorganges\\
+ $\Downarrow$\\
+ Grundlage f"ur technologischen Fortschritt in 3C-SiC-D"unnschichtherstellung
+ \end{center}
+ }
+
+ \vspace{16pt}
+
+ Grundlage zur Vermeidung von SiC-Ausscheidungen in
+ $\text{Si}_{\text{1-y}}\text{C}_{\text{y}}$ Legierungen
+
+ \begin{itemize}
+ \item Ma"sschneidern der elektronischen Eigenschaften von Si
+ \item gestreckte Heterostrukturen
+ \end{itemize}
\end{slide}
-\end{document}
+\begin{slide}
+
+ {\large\bf
+ Motivation
+ }
+
+ Die Alternative: Ionenstrahlsynthese
+
+ {\small
+
+ \begin{itemize}
+ \item Implantation 1:
+ 180 keV C$^+\rightarrow$ FZ-Si(100),
+ $D=7.9 \times 10^{17}$ cm$^{-2}$,
+ $T_{\text{i}}=500 \, ^{\circ} \text{C}$\\
+ 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$^{-2}$,
+ $T_{\text{i}}=250 \, ^{\circ} \text{C}$\\
+ Zerst"orung einzelner SiC Ausscheidungen
+ in gr"o"ser werdenden amorphen Grenzschichten
+ \item Tempern:
+ $T=1250 \, ^{\circ} \text{C}$, $t=10\text{ h}$\\
+ 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}
\begin{slide}
{\large\bf
- Crystalline silicon and cubic silicon carbide
+ SiC-Ausscheidungsvorgang
}
\vspace{8pt}
- {\bf Lattice types and unit cells:}
+ {\bf Kristallstruktur und Einheitszelle:}
\begin{itemize}
- \item Crystalline silicon (c-Si) has diamond structure\\
- $\Rightarrow {\color{si-yellow}\bullet}$ and
- ${\color{gray}\bullet}$ are Si atoms
- \item Cubic silicon carbide (3C-SiC) has zincblende structure\\
- $\Rightarrow {\color{si-yellow}\bullet}$ are Si atoms,
- ${\color{gray}\bullet}$ are C atoms
+ \item kristallines Silizium (c-Si): Diamantstruktur\\
+ ${\color{si-yellow}\bullet}$ und ${\color{gray}\bullet}$
+ $\leftarrow$ Si-Atome
+ \item kubisches SiC (3C-SiC): Zinkblende-Struktur\\
+ ${\color{si-yellow}\bullet} \leftarrow$ Si-Atome\\
+ ${\color{gray}\bullet} \leftarrow$ C-Atome
\end{itemize}
\vspace{8pt}
\begin{minipage}{8cm}
- {\bf Lattice constants:}
+ {\bf Gitterkonstanten:}
\[
4a_{\text{c-Si}}\approx5a_{\text{3C-SiC}}
\]
- {\bf Silicon density:}
+ {\bf Siliziumdichten:}
\[
\frac{n_{\text{3C-SiC}}}{n_{\text{c-Si}}}=97,66\,\%
\]
\end{slide}
- \small
\begin{slide}
{\large\bf
- Supposed Si to 3C-SiC conversion
+ SiC-Ausscheidungsvorgang
+ }
+
+ \vspace{64pt}
+
+ Hier die aus experimentellen Untersuchungen heraus vermuteten
+ Ausscheidungsvorgaenge rein.
+
+\end{slide}
+
+\begin{slide}
+
+ {\large\bf
+ SiC-Ausscheidungsvorgang
}
\small
+
\vspace{6pt}
- Supposed conversion mechanism of heavily carbon doped Si into SiC:
+ Vermuteter 3C-SiC-Ausscheidungsvorgang in c-Si:
\vspace{8pt}
\vspace{8pt}
\begin{minipage}{3.8cm}
- Formation of C-Si dumbbells on regular c-Si lattice sites
+ Bildung von C-Si Dumbbells auf regul"aren c-Si Gitterpl"atzen
\end{minipage}
\hspace{0.6cm}
\begin{minipage}{3.8cm}
- Agglomeration into large clusters (embryos)\\
+ Anh"aufung hin zu gro"sen Clustern (Embryos)\\
\end{minipage}
\hspace{0.6cm}
\begin{minipage}{3.8cm}
- Precipitation of 3C-SiC + Creation of interstitials\\
+ Ausscheidung von 3C-SiC + Erzeugung von Si-Zwischengitteratomen
\end{minipage}
\vspace{12pt}
- \begin{minipage}{7cm}
- Experimentally observed [3]:
+ Aus experimentellen Untersuchungen:
\begin{itemize}
- \item Minimal diameter of precipitation: 4 - 5 nm
- \item Equal orientation of Si and SiC (hkl)-planes
+ \item kritischer Durchmesser einer Ausscheidung: 4 - 5 nm
+ \item gleiche Orientierung der c-Si and 3C-SiC (hkl)-Ebenen
\end{itemize}
- \end{minipage}
- \begin{minipage}{6cm}
- \vspace{32pt}
- \hspace{16pt}
- {\tiny [3] J. K. N. Lindner, Appl. Phys. A 77 (2003) 27.}
- \end{minipage}
\end{slide}
\begin{slide}
{\large\bf
- Simulation details
+ Details der MD-Simulation
}
+ \vspace{12pt}
\small
- {\bf MD basics:}
+ {\bf MD-Grundlagen:}
\begin{itemize}
- \item Microscopic description of N particle system
- \item Analytical interaction potential
- \item Hamilton's equations of motion as propagation rule\\
- in 6N-dimensional phase space
- \item Observables obtained by time or ensemble averages
+ \item Mikroskopische Beschreibung eines N-Teilchensystems
+ \item Analytisches Wechselwirkungspotential
+ \item Numerische Integration der Newtonschen Bewegungsgleichung\\
+ als Propagationsvorschrift im 6N-dimensionalen Phasenraum
+ \item Observablen sind die Zeit- und/oder Ensemblemittelwerte
\end{itemize}
- {\bf Application details:}
+ {\bf Details der Simulation:}
\begin{itemize}
- \item Integrator: Velocity Verlet, timestep: $1\text{ fs}$
- \item Ensemble: isothermal-isobaric NPT [4]
+ \item Integration: Velocity Verlet, Zeitschritt: $1\text{ fs}$
+ \item Ensemble: NpT, isothermal-isobares Ensemble
\begin{itemize}
- \item Berendsen thermostat:
+ \item Berendsen Thermostat:
$\tau_{\text{T}}=100\text{ fs}$
- \item Brendsen barostat:\\
+ \item Berendsen Barostat:\\
$\tau_{\text{P}}=100\text{ fs}$,
$\beta^{-1}=100\text{ GPa}$
\end{itemize}
- \item Potential: Tersoff-like bond order potential [5]
+ \item Potential: Tersoff-"ahnliches 'bond order' Potential
+ \vspace*{12pt}
\[
E = \frac{1}{2} \sum_{i \neq j} \pot_{ij}, \quad
\pot_{ij} = f_C(r_{ij}) \left[ f_R(r_{ij}) + b_{ij} f_A(r_{ij}) \right]
\]
\end{itemize}
- {\tiny
- [4] L. Verlet, Phys. Rev. 159 (1967) 98.}\\
- {\tiny
- [5] P. Erhart and K. Albe, Phys. Rev. B 71 (2005) 35211.}
- \begin{picture}(0,0)(-240,-70)
+ \begin{picture}(0,0)(-230,-30)
\includegraphics[width=5cm]{tersoff_angle.eps}
\end{picture}
\begin{slide}
{\large\bf
- Simulation sequence
+ Zwischengitter-Konfigurationen
}
\vspace{8pt}
- Interstitial configurations:
+ Simulationssequenz:\\
\vspace{8pt}
\rput(3.5,7){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
\parbox{7cm}{
\begin{itemize}
- \item Initial configuration: $9\times9\times9$ unit cells Si
- \item Periodic boundary conditions
+ \item initiale Konfiguration:\\
+ $9\times9\times9$ Einheitszellen c-Si
+ \item periodische Randbedingungen
\item $T=0\text{ K}$, $p=0\text{ bar}$
\end{itemize}
}}}}
\rput(3.5,3.5){\rnode{insert}{\psframebox{
\parbox{7cm}{
- Insertion of C / Si atom:
+ Einf"ugen der C/Si Atome:
\begin{itemize}
- \item $(0,0,0)$ $\rightarrow$ {\color{red}tetrahedral}
+ \item $(0,0,0)$ $\rightarrow$ {\color{red}tetraedrisch}
(${\color{red}\triangleleft}$)
\item $(-1/8,-1/8,1/8)$ $\rightarrow$ {\color{green}hexagonal}
(${\color{green}\triangleright}$)
\item $(-1/8,-1/8,-1/4)$, $(-1/4,-1/4,-1/4)$\\
- $\rightarrow$ {\color{magenta}110 dumbbell}
+ $\rightarrow$ {\color{magenta}110 Dumbbell}
(${\color{magenta}\Box}$,$\circ$)
- \item random positions (critical distance check)
+ \item zuf"allige Position (Minimalabstand)
\end{itemize}
}}}}
\rput(3.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=lbb]{
\parbox{3.5cm}{
- Relaxation time: $2\, ps$
+ Relaxation ($>2$ ps)
}}}}
\ncline[]{->}{init}{insert}
\ncline[]{->}{insert}{cool}
\begin{slide}
{\large\bf
- Results
- } - Si self-interstitial runs
+ Zwischengitter-Konfigurationen
+ }
\small
\begin{minipage}[t]{4.3cm}
- \underline{Tetrahedral}\\
+ \underline{Tetraedrisch}\\
$E_f=3.41$ eV\\
\includegraphics[width=3.8cm]{si_self_int_tetra_0.eps}
\end{minipage}
\begin{minipage}[t]{4.3cm}
- \underline{110 dumbbell}\\
+ \underline{110 Dumbbell}\\
$E_f=4.39$ eV\\
\includegraphics[width=3.8cm]{si_self_int_dumbbell_0.eps}
\end{minipage}
\begin{minipage}[t]{4.3cm}
\underline{Hexagonal} \hspace{4pt}
\href{../video/si_self_int_hexa.avi}{$\rhd$}\\
- $E_f^{\star}\approx4.48$ eV (unstable!)\\
+ $E_f^{\star}\approx4.48$ eV (nicht stabil!)\\
\includegraphics[width=3.8cm]{si_self_int_hexa_0.eps}
\end{minipage}
- \underline{Random insertion}
+ \underline{zuf"allige Positionen}
\begin{minipage}{4.3cm}
$E_f=3.97$ eV\\
\begin{slide}
{\large\bf
- Results
- } - Carbon interstitial runs
+ Zwischengitter-Konfigurationen
+ }
\small
\begin{minipage}[t]{4.3cm}
- \underline{Tetrahedral}\\
+ \underline{Tetraedrisch}\\
$E_f=2.67$ eV\\
\includegraphics[width=3.8cm]{c_in_si_int_tetra_0.eps}
\end{minipage}
\begin{minipage}[t]{4.3cm}
- \underline{110 dumbbell}\\
+ \underline{110 Dumbbell}\\
$E_f=1.76$ eV\\
\includegraphics[width=3.8cm]{c_in_si_int_dumbbell_0.eps}
\end{minipage}
\begin{minipage}[t]{4.3cm}
\underline{Hexagonal} \hspace{4pt}
\href{../video/c_in_si_int_hexa.avi}{$\rhd$}\\
- $E_f^{\star}\approx5.6$ eV (unstable!)\\
+ $E_f^{\star}\approx5.6$ eV (nicht stabil!)\\
\includegraphics[width=3.8cm]{c_in_si_int_hexa_0.eps}
\end{minipage}
- \underline{Random insertion}
+ \underline{zuf"allige Positionen}
\footnotesize
$E_f=0.47$ eV\\
\includegraphics[width=3.3cm]{c_in_si_int_001db_0.eps}
\begin{picture}(0,0)(-15,-3)
- 100 dumbbell
+ 100 Dumbbell
\end{picture}
\end{minipage}
\begin{minipage}[t]{3.3cm}
\begin{slide}
{\large\bf
- Results
- } - <100> dumbbell configuration
+ Zwischengitter-Konfigurationen
+ }
+
+ Das 100 Dumbbell
\vspace{8pt}
\begin{slide}
{\large\bf
- Simulation sequence
+ Simulationen zum Ausscheidungsvorgang
}
\small
\vspace{8pt}
- SiC precipitation simulations:
+ Simulationssequenz:\\
\vspace{8pt}
\begin{pspicture}(0,0)(12,8)
% nodes
- \rput(3.5,6.5){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
+ \rput(3.5,7.0){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{
\parbox{7cm}{
\begin{itemize}
- \item Initial configuration: $31\times31\times31$ unit cells Si
- \item Periodic boundary conditions
+ \item initiale Konfiguration:\\
+ $31\times31\times31$ c-Si Einheitszellen
+ \item periodsche Randbedingungen
\item $T=450\, ^{\circ}\text{C}$, $p=0\text{ bar}$
- \item Equilibration of $E_{kin}$ and $E_{pot}$
+ \item "Aquilibrierung von $E_{\text{kin}}$ and $E_{\text{pot}}$
\end{itemize}
}}}}
\rput(3.5,3.2){\rnode{insert}{\psframebox[fillstyle=solid,fillcolor=lachs]{
\parbox{7cm}{
- Insertion of 6000 carbon atoms at constant\\
- temperature into:
+ Einf"ugen von 6000 C-Atomen\\
+ bei konstanter Temperatur
\begin{itemize}
- \item Total simulation volume {\pnode{in1}}
- \item Volume of minimal SiC precipitation {\pnode{in2}}
- \item Volume of necessary amount of Si {\pnode{in3}}
+ \item gesamte Simulationsvolumen {\pnode{in1}}
+ \item Volumen einer minimal SiC-Ausscheidung {\pnode{in2}}
+ \item Bereich der ben"otigten Si-Atome {\pnode{in3}}
\end{itemize}
}}}}
\rput(3.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=lbb]{
\parbox{3.5cm}{
- Cooling down to $20\, ^{\circ}C$
+ Abk"uhlen auf $20\, ^{\circ}\textrm{C}$
}}}}
\ncline[]{->}{init}{insert}
\ncline[]{->}{insert}{cool}
\psframe[fillstyle=solid,fillcolor=white](7.5,1.8)(13.5,7.8)
\psframe[fillstyle=solid,fillcolor=lightgray](9,3.3)(12,6.3)
\psframe[fillstyle=solid,fillcolor=gray](9.25,3.55)(11.75,6.05)
- \rput(7.9,4.8){\pnode{ins1}}
- \rput(9.22,4.4){\pnode{ins2}}
- \rput(10.5,4.8){\pnode{ins3}}
+ \rput(7.9,4.2){\pnode{ins1}}
+ \rput(9.22,3.5){\pnode{ins2}}
+ \rput(11.0,3.8){\pnode{ins3}}
\ncline[]{->}{in1}{ins1}
\ncline[]{->}{in2}{ins2}
\ncline[]{->}{in3}{ins3}
\end{slide}
+\end{document}
+
\begin{slide}
{\large\bf
- Results
- } - SiC precipitation runs
-
+ Simulationen zum Ausscheidungsvorgang
+ }
\includegraphics[width=6.3cm]{pc_si-c_c-c.eps}
\includegraphics[width=6.3cm]{pc_si-si.eps}
projects / lectures / latex.git / blobdiff