X-Git-Url: https://hackdaworld.org/gitweb/?p=lectures%2Flatex.git;a=blobdiff_plain;f=posic%2Ftalks%2Fmpi_app.tex;h=2bf8383fd95ba5a487e0f7f27062a15681b7daf9;hp=1d5cf40328ccad29f889ba6cd9b1b2cb9628088f;hb=1c838933fa76951ad4deb1164e8d2a950b6771cf;hpb=6fd78d8afe3254b0f03c367bb412bd86501e3e9e diff --git a/posic/talks/mpi_app.tex b/posic/talks/mpi_app.tex index 1d5cf40..2bf8383 100644 --- a/posic/talks/mpi_app.tex +++ b/posic/talks/mpi_app.tex @@ -7,6 +7,7 @@ \usepackage[latin1]{inputenc} \usepackage[T1]{fontenc} \usepackage{amsmath} +\usepackage{stmaryrd} \usepackage{latexsym} \usepackage{ae} @@ -20,11 +21,12 @@ \usepackage{pstricks} \usepackage{pst-node} +\usepackage{pst-grad} %\usepackage{epic} %\usepackage{eepic} -%\usepackage{layout} +\usepackage{layout} \usepackage{graphicx} \graphicspath{{../img/}} @@ -54,20 +56,41 @@ \usepackage{upgreek} +\newcommand{\headdiplom}{ +\begin{pspicture}(0,0)(0,0) +\rput(6.0,0.2){\psframebox[fillstyle=gradient,gradbegin=red,gradend=white,gradlines=1000,gradmidpoint=1,linestyle=none]{ +\begin{minipage}{14cm} +\hfill +\vspace{0.7cm} +\end{minipage} +}} +\end{pspicture} +} + +\newcommand{\headphd}{ +\begin{pspicture}(0,0)(0,0) +\rput(6.0,0.2){\psframebox[fillstyle=gradient,gradbegin=blue,gradend=white,gradlines=1000,gradmidpoint=1,linestyle=none]{ +\begin{minipage}{14cm} +\hfill +\vspace{0.7cm} +\end{minipage} +}} +\end{pspicture} +} + \begin{document} \extraslideheight{10in} -\slideframe{none} +\slideframe{plain} \pagestyle{empty} % specify width and height -\slidewidth 27.7cm -\slideheight 19.1cm +\slidewidth 26.3cm +\slideheight 19.9cm -% shift it into visual area properly -\def\slideleftmargin{3.3cm} -\def\slidetopmargin{0.6cm} +% margin +\def\slidetopmargin{-0.15cm} \newcommand{\ham}{\mathcal{H}} \newcommand{\pot}{\mathcal{V}} @@ -99,11 +122,23 @@ \newcommand{\dista}[1]{\unit[#1]{\AA}{}} \newcommand{\perc}[1]{\unit[#1]{\%}{}} -%\layout - % no vertical centering %\centerslidesfalse +% layout check +%\layout +\begin{slide} +\center +{\Huge +E\\ +F\\ +G\\ +A B C D E F G H G F E D C B A +G\\ +F\\ +E\\ +} +\end{slide} % topic @@ -132,6 +167,11 @@ \end{center} \end{slide} +% no vertical centering +\centerslidesfalse + +\ifnum1=0 + % intro \begin{slide} @@ -142,7 +182,7 @@ \vspace*{0.2cm} -\begin{minipage}{7cm} +\begin{minipage}{6.5cm} \includegraphics[width=6.5cm]{si-c_phase.eps} \begin{center} {\tiny @@ -169,62 +209,69 @@ R. I. Scace and G. A. Slack, J. Chem. Phys. 30, 1551 (1959) \begin{slide} +\vspace*{1.8cm} + \small \begin{pspicture}(0,0)(13.5,5) - \psframe*[linecolor=hb](0,0)(13.5,5) + \psframe*[linecolor=hb](-0.2,0)(12.9,5) - \pspolygon[linecolor=hlbb,fillcolor=hlbb,fillstyle=solid](5.5,1)(7,1)(7,3)(5.5,3) - \pspolygon[linecolor=hlbb,fillcolor=hlbb,fillstyle=solid](6.75,0.5)(8,2)(8,2)(6.75,3.5) + \pspolygon[linecolor=hlbb,fillcolor=hlbb,fillstyle=solid](5.2,1)(6.5,1)(6.5,3)(5.2,3) + \pspolygon[linecolor=hlbb,fillcolor=hlbb,fillstyle=solid](6.4,0.5)(7.7,2)(7.7,2)(6.4,3.5) - \rput[lt](0.2,4.6){\color{gray}PROPERTIES} + \rput[lt](0,4.6){\color{gray}PROPERTIES} - \rput[lt](0.5,4){wide band gap} - \rput[lt](0.5,3.5){high electric breakdown field} - \rput[lt](0.5,3){good electron mobility} - \rput[lt](0.5,2.5){high electron saturation drift velocity} - \rput[lt](0.5,2){high thermal conductivity} + \rput[lt](0.3,4){wide band gap} + \rput[lt](0.3,3.5){high electric breakdown field} + \rput[lt](0.3,3){good electron mobility} + \rput[lt](0.3,2.5){high electron saturation drift velocity} + \rput[lt](0.3,2){high thermal conductivity} - \rput[lt](0.5,1.5){hard and mechanically stable} - \rput[lt](0.5,1){chemically inert} + \rput[lt](0.3,1.5){hard and mechanically stable} + \rput[lt](0.3,1){chemically inert} - \rput[lt](0.5,0.5){radiation hardness} + \rput[lt](0.3,0.5){radiation hardness} - \rput[rt](13.3,4.6){\color{gray}APPLICATIONS} + \rput[rt](12.7,4.6){\color{gray}APPLICATIONS} - \rput[rt](13,3.85){high-temperature, high power} - \rput[rt](13,3.5){and high-frequency} - \rput[rt](13,3.15){electronic and optoelectronic devices} + \rput[rt](12.5,3.85){high-temperature, high power} + \rput[rt](12.5,3.5){and high-frequency} + \rput[rt](12.5,3.15){electronic and optoelectronic devices} - \rput[rt](13,2.35){material suitable for extreme conditions} - \rput[rt](13,2){microelectromechanical systems} - \rput[rt](13,1.65){abrasives, cutting tools, heating elements} + \rput[rt](12.5,2.35){material suitable for extreme conditions} + \rput[rt](12.5,2){microelectromechanical systems} + \rput[rt](12.5,1.65){abrasives, cutting tools, heating elements} - \rput[rt](13,0.85){first wall reactor material, detectors} - \rput[rt](13,0.5){and electronic devices for space} + \rput[rt](12.5,0.85){first wall reactor material, detectors} + \rput[rt](12.5,0.5){and electronic devices for space} \end{pspicture} -\begin{picture}(0,0)(0,-162) -\includegraphics[height=2.0cm]{3C_SiC_bs.eps} +\begin{picture}(0,0)(5,-162) +\includegraphics[height=2.2cm]{3C_SiC_bs.eps} \end{picture} -\begin{picture}(0,0)(-130,-162) -\includegraphics[height=2.0cm]{nasa_600c_led.eps} +\begin{picture}(0,0)(-120,-162) +\includegraphics[height=2.2cm]{nasa_600c_led.eps} \end{picture} -\begin{picture}(0,0)(-295,-162) -\includegraphics[height=2.0cm]{6h-sic_3c-sic.eps} +\begin{picture}(0,0)(-270,-162) +\includegraphics[height=2.2cm]{6h-sic_3c-sic.eps} \end{picture} %%%% -\begin{picture}(0,0)(5,65) +\begin{picture}(0,0)(10,65) \includegraphics[height=2.8cm]{sic_switch.eps} \end{picture} -\begin{picture}(0,0)(-145,65) -\includegraphics[height=2.8cm]{infineon_schottky.eps} -\end{picture} -\begin{picture}(0,0)(-260,65) +%\begin{picture}(0,0)(-243,65) +\begin{picture}(0,0)(-110,65) \includegraphics[height=2.8cm]{ise_99.eps} \end{picture} +%\begin{picture}(0,0)(-135,65) +\begin{picture}(0,0)(-100,65) +\includegraphics[height=1.2cm]{infineon_schottky.eps} +\end{picture} +\begin{picture}(0,0)(-233,65) +\includegraphics[height=2.8cm]{solar_car.eps} +\end{picture} \end{slide} @@ -233,12 +280,24 @@ R. I. Scace and G. A. Slack, J. Chem. Phys. 30, 1551 (1959) \begin{slide} {\large\bf - Polytypes of SiC + Polytypes of SiC\\[0.4cm] } - \vspace{4cm} +\includegraphics[width=3.8cm]{cubic_hex.eps}\\ +\begin{minipage}{1.9cm} +{\tiny cubic (twist)} +\end{minipage} +\begin{minipage}{2.9cm} +{\tiny hexagonal (no twist)} +\end{minipage} - \small +\begin{picture}(0,0)(-150,0) + \includegraphics[width=7cm]{polytypes.eps} +\end{picture} + +\vspace{0.6cm} + +\footnotesize \begin{tabular}{l c c c c c c} \hline @@ -254,30 +313,14 @@ Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\ \hline \end{tabular} -{\tiny - Values for $T=300$ K -} - -\begin{picture}(0,0)(-160,-155) - \includegraphics[width=7cm]{polytypes.eps} -\end{picture} -\begin{picture}(0,0)(-10,-185) - \includegraphics[width=3.8cm]{cubic_hex.eps}\\ -\end{picture} -\begin{picture}(0,0)(-10,-175) - {\tiny cubic (twist)} -\end{picture} -\begin{picture}(0,0)(-60,-175) - {\tiny hexagonal (no twist)} -\end{picture} \begin{pspicture}(0,0)(0,0) -\psellipse[linecolor=green](5.7,3.03)(0.4,0.5) +\psellipse[linecolor=green](5.7,2.10)(0.4,0.5) \end{pspicture} \begin{pspicture}(0,0)(0,0) -\psellipse[linecolor=green](5.6,1.68)(0.4,0.2) +\psellipse[linecolor=green](5.6,0.92)(0.4,0.2) \end{pspicture} \begin{pspicture}(0,0)(0,0) -\psellipse[linecolor=red](10.7,1.13)(0.4,0.2) +\psellipse[linecolor=red](10.45,0.45)(0.4,0.2) \end{pspicture} \end{slide} @@ -292,77 +335,64 @@ Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\ \small - \vspace{4pt} + \vspace{2pt} - SiC - \emph{Born from the stars, perfected on earth.} +\begin{center} + {\color{gray} + \emph{Silicon carbide --- Born from the stars, perfected on earth.} + } +\end{center} - IBS also here! - - \vspace{4pt} +\vspace{2pt} - Conventional thin film SiC growth: - \begin{itemize} - \item \underline{Sublimation growth using the modified Lely method} - \begin{itemize} - \item SiC single-crystalline seed at $T=1800 \, ^{\circ} \text{C}$ - \item Surrounded by polycrystalline SiC in a graphite crucible\\ - at $T=2100-2400 \, ^{\circ} \text{C}$ - \item Deposition of supersaturated vapor on cooler seed crystal - \end{itemize} - \item \underline{Homoepitaxial growth using CVD} - \begin{itemize} - \item Step-controlled epitaxy on off-oriented 6H-SiC substrates - \item C$_3$H$_8$/SiH$_4$/H$_2$ at $1100-1500 \, ^{\circ} \text{C}$ - \item Angle, temperature $\rightarrow$ 3C/6H/4H-SiC - \end{itemize} - \item \underline{Heteroepitaxial growth of 3C-SiC on Si using CVD/MBE} - \begin{itemize} - \item Two steps: carbonization and growth - \item $T=650-1050 \, ^{\circ} \text{C}$ - \item SiC/Si lattice mismatch $\approx$ 20 \% - \item Quality and size not yet sufficient - \end{itemize} - \end{itemize} +SiC thin films by MBE \& CVD +\begin{itemize} + \item Much progress achieved in homo/heteroepitaxial SiC thin film growth + \item \underline{Commercially available} semiconductor power devices based on + \underline{\foreignlanguage{greek}{a}-SiC} + \item Production of favored \underline{3C-SiC} material + \underline{less advanced} + \item Quality and size not yet sufficient +\end{itemize} +\begin{picture}(0,0)(-310,-20) + \includegraphics[width=2.0cm]{cree.eps} +\end{picture} - \begin{picture}(0,0)(-280,-65) - \includegraphics[width=3.8cm]{6h-sic_3c-sic.eps} - \end{picture} - \begin{picture}(0,0)(-280,-55) - \begin{minipage}{5cm} - {\tiny - NASA: 6H-SiC and 3C-SiC LED\\[-7pt] - on 6H-SiC substrate - } - \end{minipage} - \end{picture} - \begin{picture}(0,0)(-265,-150) - \includegraphics[width=2.4cm]{m_lely.eps} - \end{picture} - \begin{picture}(0,0)(-333,-175) - \begin{minipage}{5cm} - {\tiny - 1. Lid\\[-7pt] - 2. Heating\\[-7pt] - 3. Source\\[-7pt] - 4. Crucible\\[-7pt] - 5. Insulation\\[-7pt] - 6. Seed crystal - } - \end{minipage} - \end{picture} - \begin{picture}(0,0)(-230,-35) - \framebox{ - {\footnotesize\color{blue}\bf Hex: micropipes along c-axis} +\vspace{-0.2cm} + +Alternative approach: +Ion beam synthesis (IBS) of burried 3C-SiC layers in Si\hkl(1 0 0) + +\vspace{0.2cm} + +\scriptsize + +\framebox{ +\begin{minipage}{3.15cm} + \begin{center} +\includegraphics[width=3cm]{imp.eps}\\ + {\tiny + Carbon implantation } - \end{picture} - \begin{picture}(0,0)(-230,-10) - \framebox{ - \begin{minipage}{3cm} - {\footnotesize\color{blue}\bf 3C-SiC fabrication\\ - less advanced} - \end{minipage} + \end{center} +\end{minipage} +\begin{minipage}{3.15cm} + \begin{center} +\includegraphics[width=3cm]{annealing.eps}\\ + {\tiny + \unit[12]{h} annealing at \degc{1200} + } + \end{center} +\end{minipage} +} +\begin{minipage}{5.5cm} + \includegraphics[width=5.8cm]{ibs_3c-sic.eps}\\[-0.2cm] + \begin{center} + {\tiny + XTEM: single crystalline 3C-SiC in Si\hkl(1 0 0) } - \end{picture} + \end{center} +\end{minipage} \end{slide} @@ -371,215 +401,400 @@ Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\ \begin{slide} {\large\bf - Outline + Systematic investigation of C implantations into Si } - \begin{itemize} - \item Implantation of C in Si --- Overview of experimental observations - \item Utilized simulation techniques and modeled problems - \begin{itemize} - \item {\color{blue}Diploma thesis}\\ - \underline{Monte Carlo} simulations - modeling the selforganization process - leading to periodic arrays of nanometric amorphous SiC - precipitates - \item {\color{blue}Doctoral studies}\\ - Classical potential \underline{molecular dynamics} simulations - \ldots\\ - \underline{Density functional theory} calculations - \ldots\\[0.2cm] - \ldots on defects and SiC precipitation in Si - \end{itemize} - \item Summary / Conclusion / Outlook - \end{itemize} +\vspace{1.7cm} +\begin{center} +\hspace{-1.0cm} +\includegraphics[width=0.75\textwidth]{imp_inv.eps} +\end{center} \end{slide} +% outline +\begin{slide} -\end{document} +{\large\bf + Outline +} + +\vspace{1.7cm} +\begin{center} +\hspace{-1.0cm} +\includegraphics[width=0.75\textwidth]{imp_inv.eps} +\end{center} + +\begin{pspicture}(0,0)(0,0) +\rput(6.0,7.0){\rnode{init}{\psframebox[fillstyle=gradient,gradbegin=red,gradend=white,gradlines=1000,gradmidpoint=1.0,linestyle=none]{ +\begin{minipage}{11cm} +{\color{black}Diploma thesis}\\ + \underline{Monte Carlo} simulation modeling the selforganization process\\ + leading to periodic arrays of nanometric amorphous SiC precipitates +\end{minipage} +}}} +\end{pspicture} +\begin{pspicture}(0,0)(0,0) +\rput(6.0,-0.5){\rnode{init}{\psframebox[fillstyle=gradient,gradbegin=blue,gradend=white,gradmidpoint=1.0,gradlines=1000,linestyle=none]{ +\begin{minipage}{11cm} +{\color{black}Doctoral studies}\\ + Classical potential \underline{molecular dynamics} simulations \ldots\\ + \underline{Density functional theory} calculations \ldots\\[0.2cm] + \ldots on defect formation and SiC precipitation in Si +\end{minipage} +}}} +\end{pspicture} +\begin{pspicture}(0,0)(0,0) +\psellipse[linecolor=red,linewidth=0.05cm](5,3.0)(0.8,1.0) +\end{pspicture} +\begin{pspicture}(0,0)(0,0) +\psellipse[linecolor=blue,linewidth=0.05cm](8.2,3.2)(1.5,1.6) +\end{pspicture} + +\end{slide} \begin{slide} - {\large\bf - Fabrication of silicon carbide - } +\headdiplom +{\large\bf + Selforganization of nanometric amorphous SiC lamellae +} - \small +\small - Alternative approach: - Ion beam synthesis (IBS) of burried 3C-SiC layers in Si\hkl(1 0 0) - \begin{itemize} - \item \underline{Implantation step 1}\\ - 180 keV C$^+$, $D=7.9\times 10^{17}$ cm$^{-2}$, $T_{\text{i}}=500\,^{\circ}\mathrm{C}$\\ - $\Rightarrow$ box-like distribution of equally sized - and epitactically oriented SiC precipitates - - \item \underline{Implantation step 2}\\ - 180 keV C$^+$, $D=0.6\times 10^{17}$ cm$^{-2}$, $T_{\text{i}}=250\,^{\circ}\mathrm{C}$\\ - $\Rightarrow$ destruction of SiC nanocrystals - in growing amorphous interface layers - \item \underline{Annealing}\\ - $T=1250\,^{\circ}\mathrm{C}$, $t=10\,\text{h}$\\ - $\Rightarrow$ homogeneous, stoichiometric SiC layer - with sharp interfaces - \end{itemize} +\vspace{0.2cm} - \begin{minipage}{6.3cm} - \includegraphics[width=6cm]{ibs_3c-sic.eps}\\[-0.2cm] - {\tiny - XTEM micrograph of single crystalline 3C-SiC in Si\hkl(1 0 0) - } - \end{minipage} -\framebox{ - \begin{minipage}{6.3cm} - \begin{center} - {\color{blue} - Precipitation mechanism not yet fully understood! - } - \renewcommand\labelitemi{$\Rightarrow$} - \small - \underline{Understanding the SiC precipitation} - \begin{itemize} - \item significant technological progress in SiC thin film formation - \item perspectives for processes relying upon prevention of SiC precipitation - \end{itemize} - \end{center} - \end{minipage} +\begin{itemize} + \item Regularly spaced, nanometric spherical\\ + and lamellar amorphous inclusions\\ + at the upper a/c interface + \item Carbon accumulation\\ + in amorphous volumes +\end{itemize} + +\vspace{0.4cm} + +\begin{minipage}{12cm} +\includegraphics[width=9cm]{../../nlsop/img/k393abild1_e_l.eps}\\ +{\scriptsize +XTEM bright-field, \unit[180]{keV} C$^+ \rightarrow$ Si, +{\color{red}\underline{\degc{150}}}, +Dose: \unit[4.3 $\times 10^{17}$]{cm$^{-2}$} } - -\end{slide} +\end{minipage} + +\begin{picture}(0,0)(-182,-215) +\begin{minipage}{6.5cm} +\begin{center} +\includegraphics[width=6.5cm]{../../nlsop/img/eftem.eps}\\[-0.2cm] +{\scriptsize +XTEM bright-field and respective EFTEM C map +} +\end{center} +\end{minipage} +\end{picture} +\end{slide} \begin{slide} - {\large\bf - Supposed precipitation mechanism of SiC in Si - } +\headdiplom +{\large\bf + Model displaying the formation of ordered lamellae +} - \scriptsize +\vspace{0.1cm} - \vspace{0.1cm} +\begin{center} + \includegraphics[width=8.0cm]{../../nlsop/img/modell_ng_e.eps} +\end{center} - \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} +\footnotesize - \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{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 Amorphous} precipitates +\item \unit[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 Relaxation} 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 enhanced} lateral amorphisation +\item Absence of crystalline neighbours (structural information)\\ + $\rightarrow$ {\bf Stabilization} of amorphous inclusions + {\bf against recrystallization} +\end{itemize} - \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} +\end{slide} -\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} +\begin{slide} + +\headdiplom +{\large\bf + Implementation of the Monte Carlo code +} + +\small + +\begin{enumerate} + \item \underline{Amorphization / Recrystallization}\\ + Ion collision in discretized target determined by random numbers + distributed according to nuclear energy loss. + Amorphization/recrystallization probability: +\[ +p_{c \rightarrow a}(\vec{r}) = {\color{green} p_b} + {\color{blue} p_c c_C(\vec{r})} + {\color{red} \sum_{\textrm{amorphous neighbours}} \frac{p_s c_C(\vec{r'})}{(r-r')^2}} +\] +\begin{itemize} + \item {\color{green} $p_b$} normal `ballistic' amorphization + \item {\color{blue} $p_c$} carbon induced amorphization + \item {\color{red} $p_s$} stress enhanced amorphization +\end{itemize} +\[ +p_{a \rightarrow c}(\vec r) = (1 - p_{c \rightarrow a}(\vec r)) \Big(1 - \frac{\sum_{direct \, neighbours} \delta (\vec{r'})}{6} \Big) \, \textrm{,} +\] +\[ +\delta (\vec r) = \left\{ +\begin{array}{ll} + 1 & \textrm{if volume at position $\vec r$ is amorphous} \\ + 0 & \textrm{otherwise} \\ +\end{array} +\right. +\] + \item \underline{Carbon incorporation}\\ + Incorporation volume determined according to implantation profile + \item \underline{Diffusion / Sputtering} + \begin{itemize} + \item Transfer fraction of C atoms + of crystalline into neighbored amorphous volumes + \item Remove surface layer + \end{itemize} +\end{enumerate} \end{slide} \begin{slide} - {\large\bf - Supposed precipitation mechanism of SiC in Si - } +\begin{minipage}{3.7cm} +\begin{pspicture}(0,0)(0,0) +\rput(1.7,0.2){\psframebox[fillstyle=gradient,gradbegin=red,gradend=white,gradlines=1000,gradangle=10,gradmidpoint=1,linestyle=none]{ +\begin{minipage}{3.7cm} +\hfill +\vspace{0.7cm} +\end{minipage} +}} +\end{pspicture} +{\large\bf + Results +} - \scriptsize +\footnotesize - \vspace{0.1cm} +\vspace{1.2cm} - \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} +Evolution of the \ldots +\begin{itemize} + \item continuous\\ + amorphous layer + \item a/c interface + \item lamellar precipitates +\end{itemize} +\ldots reproduced!\\[1.4cm] - \begin{minipage}{4cm} - \begin{center} - C-Si dimers (dumbbells)\\[-0.1cm] - on Si interstitial sites - \end{center} +{\color{blue} +\begin{center} +Experiment \& simulation\\ +in good agreement\\[1.0cm] + +Simulation is able to model the whole depth region\\[1.2cm] +\end{center} +} + +\end{minipage} +\begin{minipage}{0.5cm} +\vfill +\end{minipage} +\begin{minipage}{8.0cm} + \vspace{-0.3cm} + \includegraphics[width=9cm]{../../nlsop/img/dosis_entwicklung_ng_e_1-2.eps}\\ + \includegraphics[width=9cm]{../../nlsop/img/dosis_entwicklung_ng_e2_2-2.eps} +\end{minipage} + +\end{slide} + +\begin{slide} + +\headdiplom +{\large\bf + Structural \& compositional details +} + +\begin{minipage}[t]{7.5cm} +\includegraphics[height=6.5cm]{../../nlsop/img/ac_cconc_ver2_e.eps}\\ +\end{minipage} +\begin{minipage}[t]{5.0cm} +\includegraphics[height=6.5cm]{../../nlsop/img/97_98_e.eps} +\end{minipage} + +\footnotesize + +\vspace{-0.1cm} + +\begin{itemize} + \item Fluctuation of C concentration in lamellae region + \item \unit[8--10]{at.\%} C saturation limit + within the respective conditions + \item Complementarily arranged and alternating sequence of layers\\ + with a high and low amount of amorphous regions + \item C accumulation in the amorphous phase / Origin of stress +\end{itemize} + +\begin{picture}(0,0)(-260,-50) +\framebox{ +\begin{minipage}{3cm} +\begin{center} +{\color{blue} +Precipitation process\\ +gets traceable\\ +by simulation! +} +\end{center} +\end{minipage} +} +\end{picture} + +\end{slide} + +\begin{slide} + +\headphd +{\large\bf + Formation of epitaxial single crystalline 3C-SiC +} + +\footnotesize + +\vspace{0.2cm} + +\begin{center} +\begin{itemize} + \item \underline{Implantation step 1}\\[0.1cm] + Almost stoichiometric dose | \unit[180]{keV} | \degc{500}\\ + $\Rightarrow$ Epitaxial {\color{blue}3C-SiC} layer \& + {\color{blue}precipitates} + \item \underline{Implantation step 2}\\[0.1cm] + Little remaining dose | \unit[180]{keV} | \degc{250}\\ + $\Rightarrow$ + Destruction/Amorphization of precipitates at layer interface + \item \underline{Annealing}\\[0.1cm] + \unit[10]{h} at \degc{1250}\\ + $\Rightarrow$ Homogeneous 3C-SiC layer with sharp interfaces +\end{itemize} +\end{center} + +\begin{minipage}{7cm} +\includegraphics[width=7cm]{ibs_3c-sic.eps} +\end{minipage} +\begin{minipage}{5cm} +\begin{pspicture}(0,0)(0,0) +\rnode{box}{ +\psframebox[fillstyle=solid,fillcolor=white,linecolor=blue,linestyle=solid]{ +\begin{minipage}{5.3cm} + \begin{center} + {\color{blue} + 3C-SiC precipitation\\ + not yet fully understood + } + \end{center} + \vspace*{0.1cm} + \renewcommand\labelitemi{$\Rightarrow$} + Details of the SiC precipitation + \begin{itemize} + \item significant technological progress\\ + in SiC thin film formation + \item perspectives for processes relying\\ + upon prevention of SiC precipitation + \end{itemize} +\end{minipage} +}} +\rput(-6.8,5.4){\pnode{h0}} +\rput(-3.0,5.4){\pnode{h1}} +\ncline[linecolor=blue]{-}{h0}{h1} +\ncline[linecolor=blue]{->}{h1}{box} +\end{pspicture} +\end{minipage} + +\end{slide} + +\begin{slide} + +\headphd +{\large\bf + Supposed precipitation mechanism of SiC in Si +} + + \scriptsize + + \vspace{0.1cm} + + \framebox{ + \begin{minipage}{3.6cm} + \begin{center} + Si \& SiC lattice structure\\[0.1cm] + \includegraphics[width=2.3cm]{sic_unit_cell.eps} + \end{center} +{\tiny + \begin{minipage}{1.7cm} +\underline{Silicon}\\ +{\color{yellow}$\bullet$} Si | {\color{gray}$\bullet$} Si\\ +$a=\unit[5.429]{\\A}$\\ +$\rho^*_{\text{Si}}=\unit[100]{\%}$ + \end{minipage} + \begin{minipage}{1.7cm} +\underline{Silicon carbide}\\ +{\color{yellow}$\bullet$} Si | {\color{gray}$\bullet$} C\\ +$a=\unit[4.359]{\\A}$\\ +$\rho^*_{\text{Si}}=\unit[97]{\%}$ + \end{minipage} +} \end{minipage} - \hspace{0.2cm} - \begin{minipage}{4.2cm} + } + \hspace{0.1cm} + \begin{minipage}{4.1cm} + \begin{center} + \includegraphics[width=3.3cm]{tem_c-si-db.eps} + \end{center} + \end{minipage} + \hspace{0.1cm} + \begin{minipage}{4.0cm} + \begin{center} + \includegraphics[width=3.3cm]{tem_3c-sic.eps} + \end{center} + \end{minipage} + + \vspace{0.1cm} + + \begin{minipage}{4.0cm} + \begin{center} + C-Si dimers (dumbbells)\\[-0.1cm] + on Si interstitial sites + \end{center} + \end{minipage} + \hspace{0.1cm} + \begin{minipage}{4.1cm} \begin{center} Agglomeration of C-Si dumbbells\\[-0.1cm] $\Rightarrow$ dark contrasts \end{center} \end{minipage} - \hspace{0.2cm} - \begin{minipage}{4cm} + \hspace{0.1cm} + \begin{minipage}{4.0cm} \begin{center} Precipitation of 3C-SiC in Si\\[-0.1cm] $\Rightarrow$ Moir\'e fringes\\[-0.1cm] @@ -587,60 +802,189 @@ r = 2 - 4 nm \end{center} \end{minipage} - \begin{minipage}{3.8cm} + \vspace{0.1cm} + + \begin{minipage}{4.0cm} \begin{center} \includegraphics[width=3.3cm]{sic_prec_seq_01.eps} \end{center} \end{minipage} - \hspace{0.6cm} - \begin{minipage}{3.8cm} + \hspace{0.1cm} + \begin{minipage}{4.1cm} \begin{center} \includegraphics[width=3.3cm]{sic_prec_seq_02.eps} \end{center} \end{minipage} - \hspace{0.6cm} - \begin{minipage}{3.8cm} + \hspace{0.1cm} + \begin{minipage}{4.0cm} \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]{ +\psline[linewidth=2pt]{->}(8.3,2)(8.8,2) +\psellipse[linecolor=blue](11.1,6.0)(0.3,0.5) +\rput{-20}{\psellipse[linecolor=blue](3.1,8.2)(0.3,0.5)} +\psline[linewidth=2pt]{->}(3.9,2)(4.4,2) +\rput(11.8,0.3){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{ $4a_{\text{Si}}=5a_{\text{SiC}}$ }}} -\rput(12.2,8){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{ +\rput(11.5,8){\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 +\rput(8.5,6.2){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{ +r = \unit[2--4]{nm} }}} -\rput(6.7,5.2){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white]{ +\end{pspicture} + +\end{slide} + +\begin{slide} + +\headphd +{\large\bf + Supposed precipitation mechanism of SiC in Si +} + + \scriptsize + + \vspace{0.1cm} + + \framebox{ + \begin{minipage}{3.6cm} + \begin{center} + Si \& SiC lattice structure\\[0.1cm] + \includegraphics[width=2.3cm]{sic_unit_cell.eps} + \end{center} +{\tiny + \begin{minipage}{1.7cm} +\underline{Silicon}\\ +{\color{yellow}$\bullet$} Si | {\color{gray}$\bullet$} Si\\ +$a=\unit[5.429]{\\A}$\\ +$\rho^*_{\text{Si}}=\unit[100]{\%}$ + \end{minipage} + \begin{minipage}{1.7cm} +\underline{Silicon carbide}\\ +{\color{yellow}$\bullet$} Si | {\color{gray}$\bullet$} C\\ +$a=\unit[4.359]{\\A}$\\ +$\rho^*_{\text{Si}}=\unit[97]{\%}$ + \end{minipage} +} + \end{minipage} + } + \hspace{0.1cm} + \begin{minipage}{4.1cm} + \begin{center} + \includegraphics[width=3.3cm]{tem_c-si-db.eps} + \end{center} + \end{minipage} + \hspace{0.1cm} + \begin{minipage}{4.0cm} + \begin{center} + \includegraphics[width=3.3cm]{tem_3c-sic.eps} + \end{center} + \end{minipage} + + \vspace{0.1cm} + + \begin{minipage}{4.0cm} + \begin{center} + C-Si dimers (dumbbells)\\[-0.1cm] + on Si interstitial sites + \end{center} + \end{minipage} + \hspace{0.1cm} + \begin{minipage}{4.1cm} + \begin{center} + Agglomeration of C-Si dumbbells\\[-0.1cm] + $\Rightarrow$ dark contrasts + \end{center} + \end{minipage} + \hspace{0.1cm} + \begin{minipage}{4.0cm} + \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} + + \vspace{0.1cm} + + \begin{minipage}{4.0cm} + \begin{center} + \includegraphics[width=3.3cm]{sic_prec_seq_01.eps} + \end{center} + \end{minipage} + \hspace{0.1cm} + \begin{minipage}{4.1cm} + \begin{center} + \includegraphics[width=3.3cm]{sic_prec_seq_02.eps} + \end{center} + \end{minipage} + \hspace{0.1cm} + \begin{minipage}{4.0cm} + \begin{center} + \includegraphics[width=3.3cm]{sic_prec_seq_03.eps} + \end{center} + \end{minipage} + +\begin{pspicture}(0,0)(0,0) +\psline[linewidth=2pt]{->}(8.3,2)(8.8,2) +\psellipse[linecolor=blue](11.1,6.0)(0.3,0.5) +\rput{-20}{\psellipse[linecolor=blue](3.1,8.2)(0.3,0.5)} +\psline[linewidth=2pt]{->}(3.9,2)(4.4,2) +\rput(11.8,0.3){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{ + $4a_{\text{Si}}=5a_{\text{SiC}}$ + }}} +\rput(11.5,8){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{ +\hkl(h k l) planes match + }}} +\rput(8.5,6.2){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{ +r = \unit[2--4]{nm} + }}} +% controversial view! +\rput(6.5,5.0){\psframebox[fillstyle=solid,opacity=0.5,fillcolor=black]{ +\begin{minipage}{14cm} +\hfill +\vspace{12cm} +\end{minipage} +}} +\rput(6.5,5.3){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white,linewidth=0.1cm]{ \begin{minipage}{10cm} \small -{\color{red}\bf Controversial views} +\vspace*{0.2cm} +\begin{center} +{\color{gray}\bf Controversial findings} +\end{center} \begin{itemize} -\item Implantations at high T (Nejim et al.) +\item High-temperature implantation {\tiny\color{gray}/Nejim~et~al./} \begin{itemize} - \item Topotactic transformation based on \cs - \item \si{} as supply reacting with further C in cleared volume + \item C incorporated {\color{blue}substitutionally} on regular Si lattice sites + \item \si{} reacting with further C in cleared volume \end{itemize} -\item Annealing behavior (Serre et al.) +\item Annealing behavior {\tiny\color{gray}/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) + \item Room temperature implantation $\rightarrow$ high C diffusion + \item Elevated temperature implantation $\rightarrow$ no C redistribution \end{itemize} + $\Rightarrow$ mobile {\color{red}\ci} opposed to + stable {\color{blue}\cs{}} configurations \item Strained silicon \& Si/SiC heterostructures + {\tiny\color{gray}/Strane~et~al./Guedj~et~al./} \begin{itemize} - \item Coherent SiC precipitates (tensile strain) + \item {\color{blue}Coherent} SiC precipitates (tensile strain) \item Incoherent SiC (strain relaxation) \end{itemize} \end{itemize} +\vspace{0.1cm} +\begin{center} +{\Huge${\lightning}$} \hspace{0.3cm} +{\color{blue}\cs{}} --- vs --- {\color{red}\ci} \hspace{0.3cm} +{\Huge${\lightning}$} +\end{center} +\vspace{0.2cm} \end{minipage} }}} \end{pspicture} @@ -649,160 +993,110 @@ r = 2 - 4 nm \begin{slide} - {\large\bf - Molecular dynamics (MD) simulations - } - - \vspace{12pt} +\headphd +{\large\bf + Utilized computational methods +} - \small +\vspace{0.3cm} - {\bf MD basics:} - \begin{itemize} - \item Microscopic description of N particle system - \item Analytical interaction potential - \item Numerical integration using Newtons equation of motion\\ - as a propagation rule in 6N-dimensional phase space - \item Observables obtained by time and/or ensemble averages - \end{itemize} - {\bf Details of the simulation:} - \begin{itemize} - \item Integration: Velocity Verlet, timestep: $1\text{ fs}$ - \item Ensemble: NpT (isothermal-isobaric) - \begin{itemize} - \item Berendsen thermostat: - $\tau_{\text{T}}=100\text{ fs}$ - \item Berendsen barostat:\\ - $\tau_{\text{P}}=100\text{ fs}$, - $\beta^{-1}=100\text{ GPa}$ - \end{itemize} - \item Erhart/Albe potential: Tersoff-like bond order potential - \vspace*{12pt} - \[ - E = \frac{1}{2} \sum_{i \neq j} \pot_{ij}, \quad - \pot_{ij} = {\color{red}f_C(r_{ij})} - \left[ f_R(r_{ij}) + {\color{blue}b_{ij}} f_A(r_{ij}) \right] - \] - \end{itemize} +\small - \begin{picture}(0,0)(-230,-30) - \includegraphics[width=5cm]{tersoff_angle.eps} - \end{picture} - -\end{slide} +{\bf Molecular dynamics (MD)}\\[0.1cm] +\scriptsize +\begin{tabular}{| p{4.5cm} | p{7.5cm} |} +\hline +System of $N$ particles & +$N=5832\pm 1$ (Defects), $N=238328+6000$ (Precipitation)\\ +Phase space propagation & +Velocity Verlet | timestep: \unit[1]{fs} \\ +Analytical interaction potential & +Tersoff-like {\color{red}short-range}, {\color{blue}bond order} potential +(Erhart/Albe) +$\displaystyle +E = \frac{1}{2} \sum_{i \neq j} \pot_{ij}, \quad + \pot_{ij} = {\color{red}f_C(r_{ij})} + \left[ f_R(r_{ij}) + {\color{blue}b_{ij}} f_A(r_{ij}) \right] +$\\ +Observables: time/ensemble averages & +NpT (isothermal-isobaric) | Berendsen thermostat/barostat\\ +\hline +\end{tabular} -\begin{slide} +\small - {\large\bf - Density functional theory (DFT) calculations - } +\vspace{0.3cm} - \small +{\bf Density functional theory (DFT)} - Basic ingredients necessary for DFT +\scriptsize - \begin{itemize} - \item \underline{Hohenberg-Kohn theorem} - ground state density $n_0(r)$ ... - \begin{itemize} - \item ... uniquely determines the ground state potential - / wavefunctions - \item ... minimizes the systems total energy - \end{itemize} - \item \underline{Born-Oppenheimer} - - $N$ moving electrons in an external potential of static nuclei -\[ -H\Psi = \left[-\sum_i^N \frac{\hbar^2}{2m}\nabla_i^2 - +\sum_i^N V_{\text{ext}}(r_i) - +\sum_{i}(3.5,-2.0){2.5}{130}{15} +\psarcn[linewidth=0.07cm,linestyle=dashed]{->}(3.5,-2.0){2.5}{230}{165} +\psarcn[linewidth=0.07cm,linestyle=dashed]{->}(3.5,-2.0){2.5}{345}{310} -\begin{pspicture}(0,0)(0,0) -\psellipse[linecolor=blue](1.5,6.75)(0.5,0.3) \end{pspicture} +\end{minipage} \end{slide} \begin{slide} +\headphd {\large\bf - C and Si self-interstitial point defects in silicon + Point defects \& defect migration } \small - \vspace*{0.3cm} + \vspace{0.2cm} -\begin{minipage}{8cm} -Procedure:\\[0.3cm] - \begin{pspicture}(0,0)(7,5) - \rput(3.5,4){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{ +\begin{minipage}[b]{7.5cm} +{\bf Defect structure}\\ + \begin{pspicture}(0,0)(7,4.4) + \rput(3.5,3.2){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=hb]{ \parbox{7cm}{ \begin{itemize} \item Creation of c-Si simulation volume @@ -810,13 +1104,13 @@ Procedure:\\[0.3cm] \item $T=0\text{ K}$, $p=0\text{ bar}$ \end{itemize} }}}} -\rput(3.5,2.1){\rnode{insert}{\psframebox{ +\rput(3.5,1.3){\rnode{insert}{\psframebox{ \parbox{7cm}{ \begin{center} Insertion of interstitial C/Si atoms \end{center} }}}} - \rput(3.5,1){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=lbb]{ + \rput(3.5,0.2){\rnode{cool}{\psframebox[fillstyle=solid,fillcolor=lbb]{ \parbox{7cm}{ \begin{center} Relaxation / structural energy minimization @@ -826,58 +1120,104 @@ Procedure:\\[0.3cm] \ncline[]{->}{insert}{cool} \end{pspicture} \end{minipage} -\begin{minipage}{5cm} - \includegraphics[width=5cm]{unit_cell_e.eps}\\ +\begin{minipage}[b]{4.5cm} +\begin{center} +\includegraphics[width=3.8cm]{unit_cell_e.eps}\\ +\end{center} +\begin{minipage}{2.21cm} +{\scriptsize +{\color{red}$\bullet$} Tetrahedral\\[-0.1cm] +{\color{green}$\bullet$} Hexagonal\\[-0.1cm] +{\color{yellow}$\bullet$} \hkl<1 0 0> DB +} +\end{minipage} +\begin{minipage}{2.21cm} +{\scriptsize +{\color{magenta}$\bullet$} \hkl<1 1 0> DB\\[-0.1cm] +{\color{cyan}$\bullet$} Bond-centered\\[-0.1cm] +{\color{black}$\bullet$} Vac. / Sub. +} +\end{minipage} \end{minipage} -\begin{minipage}{9cm} - \begin{tabular}{l c c} - \hline - & size [unit cells] & \# atoms\\ -\hline -VASP & $3\times 3\times 3$ & $216\pm 1$ \\ -Erhart/Albe & $9\times 9\times 9$ & $5832\pm 1$\\ -\hline - \end{tabular} +\vspace{0.2cm} + +\begin{minipage}[b]{6cm} +{\bf Defect formation energy}\\ +\framebox{ +$E_{\text{f}}=E-\sum_i N_i\mu_i$}\\[0.1cm] +Particle reservoir: Si \& SiC\\[0.2cm] +{\bf Binding energy}\\ +\framebox{ +$ +E_{\text{b}}= +E_{\text{f}}^{\text{comb}}- +E_{\text{f}}^{1^{\text{st}}}- +E_{\text{f}}^{2^{\text{nd}}} +$ +}\\[0.1cm] +\footnotesize +$E_{\text{b}}<0$: energetically favorable configuration\\ +$E_{\text{b}}\rightarrow 0$: non-interacting, isolated defects\\ \end{minipage} -\begin{minipage}{4cm} -{\color{red}$\bullet$} Tetrahedral\\ -{\color{green}$\bullet$} Hexagonal\\ -{\color{yellow}$\bullet$} \hkl<1 0 0> dumbbell\\ -{\color{magenta}$\bullet$} \hkl<1 1 0> dumbbell\\ -{\color{cyan}$\bullet$} Bond-centered\\ -{\color{black}$\bullet$} Vacancy / Substitutional +\begin{minipage}[b]{6cm} +{\bf Migration barrier} +\footnotesize +\begin{itemize} + \item Displace diffusing atom + \item Constrain relaxation of (diffusing) atoms + \item Record configurational energy +\end{itemize} +\begin{picture}(0,0)(-60,-33) +\includegraphics[width=4.5cm]{crt_mod.eps} +\end{picture} \end{minipage} \end{slide} \begin{slide} - \footnotesize - -\begin{minipage}{9.5cm} +\footnotesize - {\large\bf - Si self-interstitial point defects in silicon\\ - } +\headphd +{\large\bf + Si self-interstitial point defects in silicon\\[0.1cm] +} +\begin{center} \begin{tabular}{l c c c c c} \hline $E_{\text{f}}$ [eV] & \hkl<1 1 0> DB & H & T & \hkl<1 0 0> DB & V \\ \hline - VASP & \underline{3.39} & 3.42 & 3.77 & 4.41 & 3.63 \\ + \textsc{vasp} & \underline{3.39} & 3.42 & 3.77 & 4.41 & 3.63 \\ Erhart/Albe & 4.39 & 4.48$^*$ & \underline{3.40} & 5.42 & 3.13 \\ \hline -\end{tabular}\\[0.2cm] +\end{tabular}\\[0.4cm] +\end{center} -\begin{minipage}{4.7cm} -\includegraphics[width=4.7cm]{e_kin_si_hex.ps} +\begin{minipage}{3cm} +\begin{center} +\underline{Vacancy}\\ +\includegraphics[width=2.8cm]{si_pd_albe/vac.eps} +\end{center} \end{minipage} -\begin{minipage}{4.7cm} +\begin{minipage}{3cm} \begin{center} -{\tiny nearly T $\rightarrow$ T}\\ +\underline{\hkl<1 1 0> DB}\\ +\includegraphics[width=2.8cm]{si_pd_albe/110_bonds.eps} +\end{center} +\end{minipage} +\begin{minipage}{3cm} +\begin{center} +\underline{\hkl<1 0 0> DB}\\ +\includegraphics[width=2.8cm]{si_pd_albe/100_bonds.eps} +\end{center} +\end{minipage} +\begin{minipage}{3cm} +\begin{center} +\underline{Tetrahedral}\\ +\includegraphics[width=2.8cm]{si_pd_albe/tet_bonds.eps} \end{center} -\includegraphics[width=4.7cm]{nhex_tet.ps} \end{minipage}\\ \underline{Hexagonal} \hspace{2pt} @@ -885,7 +1225,7 @@ Erhart/Albe & $9\times 9\times 9$ & $5832\pm 1$\\ \framebox{ \begin{minipage}{2.7cm} $E_{\text{f}}^*=4.48\text{ eV}$\\ -\includegraphics[width=2.7cm]{si_pd_albe/hex_a.eps} +\includegraphics[width=2.7cm]{si_pd_albe/hex_a_bonds.eps} \end{minipage} \begin{minipage}{0.4cm} \begin{center} @@ -894,28 +1234,14 @@ $\Rightarrow$ \end{minipage} \begin{minipage}{2.7cm} $E_{\text{f}}=3.96\text{ eV}$\\ -\includegraphics[width=2.8cm]{si_pd_albe/hex.eps} +\includegraphics[width=2.8cm]{si_pd_albe/hex_bonds.eps} \end{minipage} } -\begin{minipage}{2.9cm} -\begin{flushright} -\underline{Vacancy}\\ -\includegraphics[width=3.0cm]{si_pd_albe/vac.eps} -\end{flushright} -\end{minipage} - -\end{minipage} -\begin{minipage}{3.5cm} - -\begin{flushright} -\underline{\hkl<1 1 0> dumbbell}\\ -\includegraphics[width=3.0cm]{si_pd_albe/110.eps}\\ -\underline{Tetrahedral}\\ -\includegraphics[width=3.0cm]{si_pd_albe/tet.eps}\\ -\underline{\hkl<1 0 0> dumbbell}\\ -\includegraphics[width=3.0cm]{si_pd_albe/100.eps} -\end{flushright} - +\begin{minipage}{5.5cm} +\begin{center} +{\tiny nearly T $\rightarrow$ T}\\ +\end{center} +\includegraphics[width=6.0cm]{nhex_tet.ps} \end{minipage} \end{slide} @@ -924,71 +1250,73 @@ $E_{\text{f}}=3.96\text{ eV}$\\ \footnotesize - {\large\bf - C interstitial point defects in silicon\\[-0.1cm] - } +\headphd +{\large\bf + C interstitial point defects in silicon\\ +} \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 & \cs{} \& \si\\ + $E_{\text{f}}$ [eV] & T & H & \hkl<1 0 0> DB & \hkl<1 1 0> DB & S & B & + {\color{black} \cs{} \& \si}\\ \hline - 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} \\ + \textsc{vasp} & unstable & unstable & \underline{3.72} & 4.16 & 1.95 & 4.66 & {\color{green}4.17}\\ + Erhart/Albe & 6.09 & 9.05$^*$ & \underline{3.88} & 5.18 & {\color{red}0.75} & 5.59$^*$ & {\color{green}4.43} \\ \hline \end{tabular}\\[0.1cm] \framebox{ -\begin{minipage}{2.7cm} +\begin{minipage}{2.8cm} \underline{Hexagonal} \hspace{2pt} \href{../video/c_in_si_int_hexa.avi}{$\rhd$}\\ $E_{\text{f}}^*=9.05\text{ eV}$\\ -\includegraphics[width=2.7cm]{c_pd_albe/hex.eps} +\includegraphics[width=2.8cm]{c_pd_albe/hex_bonds.eps} \end{minipage} \begin{minipage}{0.4cm} \begin{center} $\Rightarrow$ \end{center} \end{minipage} -\begin{minipage}{2.7cm} +\begin{minipage}{2.8cm} \underline{\hkl<1 0 0>}\\ $E_{\text{f}}=3.88\text{ eV}$\\ -\includegraphics[width=2.7cm]{c_pd_albe/100.eps} +\includegraphics[width=2.8cm]{c_pd_albe/100_bonds.eps} \end{minipage} } -\begin{minipage}{2cm} +\begin{minipage}{1.4cm} \hfill \end{minipage} -\begin{minipage}{3cm} +\begin{minipage}{3.0cm} \begin{flushright} \underline{Tetrahedral}\\ -\includegraphics[width=3.0cm]{c_pd_albe/tet.eps} +\includegraphics[width=3.0cm]{c_pd_albe/tet_bonds.eps} \end{flushright} \end{minipage} \framebox{ -\begin{minipage}{2.7cm} +\begin{minipage}{2.8cm} \underline{Bond-centered}\\ $E_{\text{f}}^*=5.59\text{ eV}$\\ -\includegraphics[width=2.7cm]{c_pd_albe/bc.eps} +\includegraphics[width=2.8cm]{c_pd_albe/bc_bonds.eps} \end{minipage} \begin{minipage}{0.4cm} \begin{center} $\Rightarrow$ \end{center} \end{minipage} -\begin{minipage}{2.7cm} +\begin{minipage}{2.8cm} \underline{\hkl<1 1 0> dumbbell}\\ $E_{\text{f}}=5.18\text{ eV}$\\ -\includegraphics[width=2.7cm]{c_pd_albe/110.eps} +\includegraphics[width=2.8cm]{c_pd_albe/110_bonds.eps} \end{minipage} } -\begin{minipage}{2cm} +\begin{minipage}{1.4cm} \hfill \end{minipage} -\begin{minipage}{3cm} +\begin{minipage}{3.0cm} \begin{flushright} \underline{Substitutional}\\ -\includegraphics[width=3.0cm]{c_pd_albe/sub.eps} +\includegraphics[width=3.0cm]{c_pd_albe/sub_bonds.eps} \end{flushright} \end{minipage} @@ -996,82 +1324,46 @@ $E_{\text{f}}=5.18\text{ eV}$\\ \begin{slide} -\footnotesize +\headphd +{\large\bf\boldmath + C-Si dimer \& bond-centered interstitial configuration +} - {\large\bf\boldmath - C \hkl<1 0 0> dumbbell interstitial configuration\\ - } +\footnotesize -{\tiny -\begin{tabular}{l c c c c c c c c} -\hline - Distances [nm] & $r(1C)$ & $r(2C)$ & $r(3C)$ & $r(12)$ & $r(13)$ & $r(34)$ & $r(23)$ & $r(25)$ \\ -\hline -Erhart/Albe & 0.175 & 0.329 & 0.186 & 0.226 & 0.300 & 0.343 & 0.423 & 0.425 \\ -VASP & 0.174 & 0.341 & 0.182 & 0.229 & 0.286 & 0.347 & 0.422 & 0.417 \\ -\hline -\end{tabular}\\[0.2cm] -\begin{tabular}{l c c c c } -\hline - Angles [$^{\circ}$] & $\theta_1$ & $\theta_2$ & $\theta_3$ & $\theta_4$ \\ -\hline -Erhart/Albe & 140.2 & 109.9 & 134.4 & 112.8 \\ -VASP & 130.7 & 114.4 & 146.0 & 107.0 \\ -\hline -\end{tabular}\\[0.2cm] -\begin{tabular}{l c c c} -\hline - Displacements [nm]& $a$ & $b$ & $|a|+|b|$ \\ -\hline -Erhart/Albe & 0.084 & -0.091 & 0.175 \\ -VASP & 0.109 & -0.065 & 0.174 \\ -\hline -\end{tabular}\\[0.6cm] -} +\vspace{0.1cm} -\begin{minipage}{3.0cm} +\begin{minipage}[t]{4.1cm} +{\bf\boldmath C \hkl<1 0 0> DB interstitial}\\[0.1cm] +\begin{minipage}{2.0cm} \begin{center} \underline{Erhart/Albe} -\includegraphics[width=3.0cm]{c_pd_albe/100_cmp.eps} +\includegraphics[width=2.0cm]{c_pd_albe/100_cmp.eps} \end{center} \end{minipage} -\begin{minipage}{3.0cm} +\begin{minipage}{2.0cm} \begin{center} -\underline{VASP} -\includegraphics[width=3.0cm]{c_pd_vasp/100_cmp.eps} +\underline{\textsc{vasp}} +\includegraphics[width=2.0cm]{c_pd_vasp/100_cmp.eps} \end{center} -\end{minipage}\\ - -\begin{picture}(0,0)(-185,10) -\includegraphics[width=6.8cm]{100-c-si-db_cmp.eps} -\end{picture} -\begin{picture}(0,0)(-280,-150) -\includegraphics[width=3.3cm]{c_pd_vasp/eden.eps} -\end{picture} - -\begin{pspicture}(0,0)(0,0) -\psellipse[linecolor=green](5.18,5.92)(0.5,0.3) -\psellipse[linecolor=red](3.45,5.92)(1.0,0.4) -\psellipse[linecolor=blue](2.7,6.92)(0.9,0.2) -\psellipse[linecolor=blue](4.65,6.92)(0.9,0.2) -\end{pspicture} - -\end{slide} - -\begin{slide} - -\small - -\begin{minipage}{8.5cm} - - {\large\bf - Bond-centered interstitial configuration\\[-0.1cm] - } - -\begin{minipage}{3.0cm} -\includegraphics[width=2.8cm]{c_pd_vasp/bc_2333.eps}\\ +\end{minipage}\\[0.2cm] +Si-C-Si bond angle $\rightarrow$ \unit[180]{$^{\circ}$}\\ +$\Rightarrow$ $sp$ hybridization\\[0.1cm] +Si-Si-Si bond angle $\rightarrow$ \unit[120]{$^{\circ}$}\\ +$\Rightarrow$ $sp^2$ hybridization +\begin{center} +\includegraphics[width=3.4cm]{c_pd_vasp/eden.eps}\\[-0.1cm] +{\tiny Charge density isosurface} +\end{center} +\end{minipage} +\begin{minipage}{0.2cm} +\hfill \end{minipage} -\begin{minipage}{5.2cm} +\begin{minipage}[t]{8.1cm} +\begin{flushright} +{\bf Bond-centered interstitial}\\[0.1cm] +\begin{minipage}{4.4cm} +%\scriptsize \begin{itemize} \item Linear Si-C-Si bond \item Si: one C \& 3 Si neighbours @@ -1080,6 +1372,11 @@ VASP & 0.109 & -0.065 & 0.174 \\ Real local minimum! \end{itemize} \end{minipage} +\begin{minipage}{2.7cm} +%\includegraphics[width=2.8cm]{c_pd_vasp/bc_2333.eps}\\ +\vspace{0.2cm} +\includegraphics[width=2.8cm]{c_pd_albe/bc_bonds.eps}\\ +\end{minipage} \framebox{ \tiny @@ -1135,582 +1432,336 @@ VASP & 0.109 & -0.065 & 0.174 \\ \end{flushright} \end{minipage} \end{minipage} -}\\[0.1cm] +}\\[0.4cm] -\framebox{ -\begin{minipage}{4.5cm} -\includegraphics[width=4cm]{c_100_mig_vasp/im_spin_diff.eps} -\end{minipage} -\begin{minipage}{3.5cm} +%\framebox{ +\begin{minipage}{3.0cm} +%\scriptsize +\underline{Charge density}\\ {\color{gray}$\bullet$} Spin up\\ {\color{green}$\bullet$} Spin down\\ {\color{blue}$\bullet$} Resulting spin up\\ {\color{yellow}$\bullet$} Si atoms\\ {\color{red}$\bullet$} C atom \end{minipage} -} - +\begin{minipage}{3.6cm} +\includegraphics[width=3.8cm]{c_100_mig_vasp/im_spin_diff.eps} \end{minipage} -\begin{minipage}{4.2cm} -\begin{flushright} -\includegraphics[width=4.3cm]{c_pd_vasp/bc_2333_ksl.ps}\\ -{\color{green}$\Box$} {\tiny unoccupied}\\ -{\color{red}$\bullet$} {\tiny occupied} +%} + \end{flushright} + \end{minipage} +\begin{pspicture}(0,0)(0,0) +\psline[linecolor=gray,linewidth=0.05cm](-7.8,-8.7)(-7.8,0) +\end{pspicture} \end{slide} \begin{slide} - {\large\bf\boldmath - Migration of the C \hkl<1 0 0> dumbbell interstitial - } +\headphd +{\large\bf\boldmath + C interstitial migration --- ab initio +} \scriptsize - {\small Investigated pathways} +\vspace{0.1cm} -\begin{minipage}{8.5cm} -\begin{minipage}{8.3cm} -\underline{\hkl<0 0 -1> $\rightarrow$ \hkl<0 0 1>}\\ -\begin{minipage}{2.4cm} -\includegraphics[width=2.4cm]{c_pd_vasp/100_2333.eps} +\begin{minipage}{6.8cm} +\framebox{\hkl[0 0 -1] $\rightarrow$ \hkl[0 0 1]}\\ +\begin{minipage}{2.0cm} +\includegraphics[width=2.0cm]{c_pd_vasp/100_2333.eps} \end{minipage} -\begin{minipage}{0.4cm} -$\rightarrow$ -\end{minipage} -\begin{minipage}{2.4cm} -\includegraphics[width=2.4cm]{c_pd_vasp/bc_2333.eps} -\end{minipage} -\begin{minipage}{0.4cm} -$\rightarrow$ -\end{minipage} -\begin{minipage}{2.4cm} -\includegraphics[width=2.4cm]{c_pd_vasp/100_next_2333.eps} -\end{minipage} -\end{minipage}\\ -\begin{minipage}{8.3cm} -\underline{\hkl<0 0 -1> $\rightarrow$ \hkl<0 -1 0>}\\ -\begin{minipage}{2.4cm} -\includegraphics[width=2.4cm]{c_pd_vasp/100_2333.eps} -\end{minipage} -\begin{minipage}{0.4cm} +\begin{minipage}{0.2cm} $\rightarrow$ \end{minipage} -\begin{minipage}{2.4cm} -\includegraphics[width=2.4cm]{c_pd_vasp/00-1-0-10_2333.eps} +\begin{minipage}{2.0cm} +\includegraphics[width=2.0cm]{c_pd_vasp/bc_2333.eps} \end{minipage} -\begin{minipage}{0.4cm} +\begin{minipage}{0.2cm} $\rightarrow$ \end{minipage} -\begin{minipage}{2.4cm} -\includegraphics[width=2.4cm]{c_pd_vasp/0-10_2333.eps} -\end{minipage} -\end{minipage}\\ -\begin{minipage}{8.3cm} -\underline{\hkl<0 0 -1> $\rightarrow$ \hkl<0 -1 0> (in place)}\\ -\begin{minipage}{2.4cm} -\includegraphics[width=2.4cm]{c_pd_vasp/100_2333.eps} +\begin{minipage}{2.0cm} +\includegraphics[width=2.0cm]{c_pd_vasp/100_next_2333.eps} +\end{minipage}\\[0.1cm] +Spin polarization\\ +$\Rightarrow$ BC configuration constitutes local minimum\\ +$\Rightarrow$ Migration barrier to reach BC | $\Delta E=\unit[1.2]{eV}$ +\end{minipage} +\begin{minipage}{5.4cm} +\includegraphics[width=6.0cm]{im_00-1_nosym_sp_fullct_thesis_vasp_s.ps} +\end{minipage}\\[0.2cm] +%\hrule +% +\begin{minipage}{6.8cm} +\framebox{\hkl[0 0 -1] $\rightarrow$ \hkl[0 -1 0]}\\ +\begin{minipage}{2.0cm} +\includegraphics[width=2.0cm]{c_pd_vasp/100_2333.eps} \end{minipage} -\begin{minipage}{0.4cm} +\begin{minipage}{0.2cm} $\rightarrow$ \end{minipage} -\begin{minipage}{2.4cm} -\includegraphics[width=2.4cm]{c_pd_vasp/00-1_ip0-10_2333.eps} +\begin{minipage}{2.0cm} +\includegraphics[width=2.0cm]{c_pd_vasp/00-1-0-10_2333.eps} \end{minipage} -\begin{minipage}{0.4cm} +\begin{minipage}{0.2cm} $\rightarrow$ \end{minipage} -\begin{minipage}{2.4cm} -\includegraphics[width=2.4cm]{c_pd_vasp/0-10_ip_2333.eps} -\end{minipage} -\end{minipage} -\end{minipage} -\framebox{ -\begin{minipage}{4.2cm} - {\small Constrained relaxation\\ - technique (CRT) method}\\ -\includegraphics[width=4cm]{crt_orig.eps} -\begin{itemize} - \item Constrain diffusing atom - \item Static constraints -\end{itemize} -\vspace*{0.3cm} - {\small Modifications}\\ -\includegraphics[width=4cm]{crt_mod.eps} -\begin{itemize} - \item Constrain all atoms - \item Update individual\\ - constraints -\end{itemize} -\end{minipage} -} - -\end{slide} - -\begin{slide} - - {\large\bf\boldmath - Migration of the C \hkl<1 0 0> dumbbell interstitial - } - -\scriptsize - -\framebox{ -\begin{minipage}{5.9cm} -\begin{flushleft} -\includegraphics[width=5.8cm]{im_00-1_nosym_sp_fullct_thesis.ps}\\[0.45cm] -\end{flushleft} -\begin{center} -\begin{picture}(0,0)(60,0) -\includegraphics[width=1cm]{vasp_mig/00-1.eps} -\end{picture} -\begin{picture}(0,0)(-5,0) -\includegraphics[width=1cm]{vasp_mig/bc_00-1_sp.eps} -\end{picture} -\begin{picture}(0,0)(-55,0) -\includegraphics[width=1cm]{vasp_mig/bc.eps} -\end{picture} -\begin{picture}(0,0)(12.5,10) -\includegraphics[width=1cm]{110_arrow.eps} -\end{picture} -\begin{picture}(0,0)(90,0) -\includegraphics[height=0.9cm]{001_arrow.eps} -\end{picture} -\end{center} -\vspace*{0.35cm} -\end{minipage} -} -\begin{minipage}{0.3cm} -\hfill -\end{minipage} -\framebox{ -\begin{minipage}{5.9cm} -\begin{flushright} -\includegraphics[width=5.9cm]{vasp_mig/00-1_0-10_nosym_sp_fullct.ps}\\[0.5cm] -\end{flushright} -\begin{center} -\begin{picture}(0,0)(60,0) -\includegraphics[width=1cm]{vasp_mig/00-1_a.eps} -\end{picture} -\begin{picture}(0,0)(5,0) -\includegraphics[width=1cm]{vasp_mig/00-1_0-10_sp.eps} -\end{picture} -\begin{picture}(0,0)(-55,0) -\includegraphics[width=1cm]{vasp_mig/0-10.eps} -\end{picture} -\begin{picture}(0,0)(12.5,10) -\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*{0.3cm} -\end{minipage}\\ -} - -\vspace*{0.05cm} - -\framebox{ -\begin{minipage}{5.9cm} -\begin{flushleft} -\includegraphics[width=5.9cm]{vasp_mig/00-1_ip0-10_nosym_sp_fullct.ps}\\[0.6cm] -\end{flushleft} -\begin{center} -\begin{picture}(0,0)(60,0) -\includegraphics[width=0.9cm]{vasp_mig/00-1_b.eps} -\end{picture} -\begin{picture}(0,0)(10,0) -\includegraphics[width=0.9cm]{vasp_mig/00-1_ip0-10_sp.eps} -\end{picture} -\begin{picture}(0,0)(-60,0) -\includegraphics[width=0.9cm]{vasp_mig/0-10_b.eps} -\end{picture} -\begin{picture}(0,0)(12.5,10) -\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*{0.3cm} -\end{minipage} -} -\begin{minipage}{0.3cm} -\hfill -\end{minipage} -\begin{minipage}{6.5cm} -VASP results -\begin{itemize} - \item Energetically most favorable path - \begin{itemize} - \item Path 2 - \item Activation energy: $\approx$ 0.9 eV - \item Experimental values: 0.73 ... 0.87 eV - \end{itemize} - $\Rightarrow$ {\color{blue}Diffusion} path identified! - \item Reorientation (path 3) - \begin{itemize} - \item More likely composed of two consecutive steps of type 2 - \item Experimental values: 0.77 ... 0.88 eV - \end{itemize} - $\Rightarrow$ {\color{blue}Reorientation} transition identified! -\end{itemize} +\begin{minipage}{2.0cm} +\includegraphics[width=2.0cm]{c_pd_vasp/0-10_2333.eps} +\end{minipage}\\[0.1cm] +$\Delta E=\unit[0.9]{eV}$ | Experimental values: \unit[0.70--0.87]{eV}\\ +$\Rightarrow$ {\color{red}Migration mechanism identified!}\\ +Note: Change in orientation \end{minipage} +\begin{minipage}{5.4cm} +\includegraphics[width=6.0cm]{00-1_0-10_vasp_s.ps} +\end{minipage}\\[0.1cm] +% +\begin{center} +Reorientation pathway composed of two consecutive processes of the above type +\end{center} \end{slide} \begin{slide} - {\large\bf\boldmath - Migration of the C \hkl<1 0 0> dumbbell interstitial - } +\headphd +{\large\bf\boldmath + C interstitial migration --- analytical potential +} \scriptsize - \vspace{0.1cm} - -\begin{minipage}{6.5cm} - -\framebox{ -\begin{minipage}[t]{5.9cm} -\begin{flushleft} -\includegraphics[width=5.9cm]{bc_00-1.ps}\\[2.35cm] -\end{flushleft} -\begin{center} -\begin{pspicture}(0,0)(0,0) -\psframe[linecolor=red,fillstyle=none](-2.8,1.35)(3.3,2.7) -\end{pspicture} -\begin{picture}(0,0)(60,-50) -\includegraphics[width=1cm]{albe_mig/bc_00-1_red_00.eps} -\end{picture} -\begin{picture}(0,0)(5,-50) -\includegraphics[width=1cm]{albe_mig/bc_00-1_red_01.eps} -\end{picture} -\begin{picture}(0,0)(-55,-50) -\includegraphics[width=1cm]{albe_mig/bc_00-1_red_02.eps} -\end{picture} -\begin{picture}(0,0)(12.5,-40) -\includegraphics[width=1cm]{110_arrow.eps} -\end{picture} -\begin{picture}(0,0)(90,-45) -\includegraphics[height=0.9cm]{001_arrow.eps} -\end{picture}\\ -\begin{pspicture}(0,0)(0,0) -\psframe[linecolor=blue,fillstyle=none](-2.8,0)(3.3,1.6) -\end{pspicture} -\begin{picture}(0,0)(60,-15) -\includegraphics[width=0.9cm]{albe_mig/bc_00-1_01.eps} -\end{picture} -\begin{picture}(0,0)(35,-15) -\includegraphics[width=0.9cm]{albe_mig/bc_00-1_02.eps} -\end{picture} -\begin{picture}(0,0)(-5,-15) -\includegraphics[width=0.9cm]{albe_mig/bc_00-1_03.eps} -\end{picture} -\begin{picture}(0,0)(-55,-15) -\includegraphics[width=0.9cm]{albe_mig/bc_00-1_04.eps} -\end{picture} -\begin{picture}(0,0)(12.5,-5) -\includegraphics[width=1cm]{100_arrow.eps} -\end{picture} -\begin{picture}(0,0)(90,-15) -\includegraphics[height=0.9cm]{010_arrow.eps} -\end{picture} -\end{center} -\end{minipage} -}\\[0.1cm] +\vspace{0.3cm} -\begin{minipage}{5.9cm} -Erhart/Albe results +\begin{minipage}[t]{6.0cm} +{\bf\boldmath BC to \hkl[0 0 -1] transition}\\[0.2cm] +\includegraphics[width=6.0cm]{bc_00-1_albe_s.ps}\\ \begin{itemize} - \item Lowest activation energy: $\approx$ 2.2 eV - \item 2.4 times higher than VASP + \item Lowermost migration barrier + \item $\Delta E \approx \unit[2.2]{eV}$ + \item 2.4 times higher than ab initio result \item Different pathway \end{itemize} \end{minipage} - -\end{minipage} -\begin{minipage}{6.5cm} - -\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} -%\end{minipage} -%}\\[0.2cm] -% -%\framebox{ -%\begin{minipage}{5.9cm} -\includegraphics[width=5.9cm]{00-1_110_0-10_mig_albe.ps} +\begin{minipage}[t]{0.2cm} +\hfill \end{minipage} -}\\[0.1cm] - -\begin{minipage}{5.9cm} -Transition involving \ci{} \hkl<1 1 0> +\begin{minipage}[t]{6.0cm} +{\bf\boldmath Transition involving a \hkl<1 1 0> configuration} +\vspace{0.1cm} \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 + \item Minima of the \hkl[0 0 -1] to \hkl[0 -1 0] transition\\ + $\rightarrow$ \ci{} \hkl<1 1 0> DB \end{itemize} \vspace{0.1cm} +\includegraphics[width=6.0cm]{00-1_110_0-10_mig_albe.ps} +\begin{itemize} + \item $\Delta E \approx \unit[2.2]{eV} \text{ \& } \unit[0.9]{eV}$ + \item 2.4 -- 3.4 times higher than ab initio result + \item After all: Change of the DB orientation +\end{itemize} +\end{minipage} + +\vspace{0.5cm} \begin{center} -{\color{blue}Overestimated diffusion barrier} +{\color{red}\bf Drastically overestimated diffusion barrier} \end{center} -\end{minipage} -\end{minipage} +\begin{pspicture}(0,0)(0,0) +\psline[linewidth=0.05cm,linecolor=gray](6.1,1.0)(6.1,9.3) +\end{pspicture} \end{slide} \begin{slide} - {\large\bf\boldmath - Combinations with a C-Si \hkl<1 0 0>-type interstitial - } - -\small - -\vspace*{0.1cm} +\headphd +{\large\bf\boldmath + Defect combinations +} -Binding energy: -$ -E_{\text{b}}= -E_{\text{f}}^{\text{defect combination}}- -E_{\text{f}}^{\text{C \hkl<0 0 -1> dumbbell}}- -E_{\text{f}}^{\text{2nd defect}} -$ +\footnotesize -\vspace*{0.1cm} +\vspace{0.3cm} +\begin{minipage}{9cm} +{\bf + Summary of combinations}\\[0.1cm] {\scriptsize \begin{tabular}{l c c c c c c} \hline $E_{\text{b}}$ [eV] & 1 & 2 & 3 & 4 & 5 & R\\ \hline - \hkl<0 0 -1> & {\color{red}-0.08} & -1.15 & {\color{red}-0.08} & 0.04 & -1.66 & -0.19\\ - \hkl<0 0 1> & 0.34 & 0.004 & -2.05 & 0.26 & -1.53 & -0.19\\ - \hkl<0 -1 0> & {\color{orange}-2.39} & -0.17 & {\color{green}-0.10} & {\color{blue}-0.27} & {\color{magenta}-1.88} & {\color{gray}-0.05}\\ - \hkl<0 1 0> & {\color{cyan}-2.25} & -1.90 & {\color{cyan}-2.25} & {\color{purple}-0.12} & {\color{violet}-1.38} & {\color{yellow}-0.06}\\ - \hkl<-1 0 0> & {\color{orange}-2.39} & -0.36 & {\color{cyan}-2.25} & {\color{purple}-0.12} & {\color{magenta}-1.88} & {\color{gray}-0.05}\\ - \hkl<1 0 0> & {\color{cyan}-2.25} & -2.16 & {\color{green}-0.10} & {\color{blue}-0.27} & {\color{violet}-1.38} & {\color{yellow}-0.06}\\ + \hkl[0 0 -1] & {\color{red}-0.08} & -1.15 & {\color{red}-0.08} & 0.04 & -1.66 & -0.19\\ + \hkl[0 0 1] & 0.34 & 0.004 & -2.05 & 0.26 & -1.53 & -0.19\\ + \hkl[0 -1 0] & {\color{orange}-2.39} & -0.17 & {\color{green}-0.10} & {\color{blue}-0.27} & {\color{magenta}-1.88} & {\color{gray}-0.05}\\ + \hkl[0 1 0] & {\color{cyan}-2.25} & -1.90 & {\color{cyan}-2.25} & {\color{purple}-0.12} & {\color{violet}-1.38} & {\color{yellow}-0.06}\\ + \hkl[-1 0 0] & {\color{orange}-2.39} & -0.36 & {\color{cyan}-2.25} & {\color{purple}-0.12} & {\color{magenta}-1.88} & {\color{gray}-0.05}\\ + \hkl[1 0 0] & {\color{cyan}-2.25} & -2.16 & {\color{green}-0.10} & {\color{blue}-0.27} & {\color{violet}-1.38} & {\color{yellow}-0.06}\\ \hline - C substitutional (C$_{\text{S}}$) & 0.26 & -0.51 & -0.93 & -0.15 & 0.49 & -0.05\\ - Vacancy & -5.39 ($\rightarrow$ C$_{\text{S}}$) & -0.59 & -3.14 & -0.54 & -0.50 & -0.31\\ + C$_{\text{sub}}$ & 0.26 & -0.51 & -0.93 & -0.15 & 0.49 & -0.05\\ + Vacancy & -5.39 ($\rightarrow$ C$_{\text{sub}}$) & -0.59 & -3.14 & -0.54 & -0.50 & -0.31\\ \hline \end{tabular} } +\vspace{0.2cm} +\begin{center} +{\color{blue} + $E_{\text{b}}$ explainable by stress compensation / increase +} +\end{center} +\end{minipage} +\begin{minipage}{3cm} +\includegraphics[width=3.5cm]{comb_pos.eps} +\end{minipage} -\vspace*{0.3cm} - -\footnotesize +\vspace{0.2cm} -\begin{minipage}[t]{3.8cm} -\underline{\hkl<1 0 0> at position 1}\\[0.1cm] -\includegraphics[width=3.5cm]{00-1dc/2-25.eps} +{\bf\boldmath Combinations of \hkl<1 0 0>-type interstitials}\\[0.2cm] +\begin{minipage}[t]{3.2cm} +\underline{\hkl[1 0 0] at position 1}\\[0.1cm] +\includegraphics[width=2.8cm]{00-1dc/2-25.eps} \end{minipage} -\begin{minipage}[t]{3.5cm} -\underline{\hkl<0 -1 0> at position 1}\\[0.1cm] -\includegraphics[width=3.2cm]{00-1dc/2-39.eps} +\begin{minipage}[t]{3.0cm} +\underline{\hkl[0 -1 0] at position 1}\\[0.1cm] +\includegraphics[width=2.8cm]{00-1dc/2-39.eps} \end{minipage} -\begin{minipage}[t]{5.5cm} +\begin{minipage}[t]{6.1cm} +\vspace{0.7cm} \begin{itemize} - \item $E_{\text{b}}=0$ $\Leftrightarrow$ non-interacting defects\\ - $E_{\text{b}} \rightarrow 0$ for increasing distance (R) - \item Stress compensation / increase - \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) + \item \ci{} agglomeration energetically favorable + \item Most favorable: C clustering\\ + {\color{red}However \ldots}\\ + \ldots high migration barrier ($>4\,\text{eV}$)\\ + \ldots entropy: + $4\times{\color{cyan}[-2.25]}$ versus + $2\times{\color{orange}[-2.39]}$ \end{itemize} +\begin{center} +{\color{blue}\ci{} agglomeration / no C clustering} +\end{center} \end{minipage} -\begin{picture}(0,0)(-295,-130) -\includegraphics[width=3.5cm]{comb_pos.eps} -\end{picture} - \end{slide} \begin{slide} - {\large\bf\boldmath - Combinations of C-Si \hkl<1 0 0>-type interstitials - } - -\small - -\vspace*{0.1cm} +\headphd +{\large\bf\boldmath + Defect combinations +} -Energetically most favorable combinations along \hkl<1 1 0> +\footnotesize -\vspace*{0.1cm} +\vspace{0.3cm} +\begin{minipage}{9cm} +{\bf + Summary of combinations}\\[0.1cm] {\scriptsize \begin{tabular}{l c c c c c c} \hline - & 1 & 2 & 3 & 4 & 5 & 6\\ -\hline -$E_{\text{b}}$ [eV] & -2.39 & -1.88 & -0.59 & -0.31 & -0.24 & -0.21 \\ -C-C distance [\AA] & 1.4 & 4.6 & 6.5 & 8.6 & 10.5 & 10.8 \\ -Type & \hkl<-1 0 0> & \hkl<1 0 0> & \hkl<1 0 0> & \hkl<1 0 0> & \hkl<1 0 0> & \hkl<1 0 0>, \hkl<0 -1 0>\\ + $E_{\text{b}}$ [eV] & 1 & 2 & 3 & 4 & 5 & R\\ + \hline + \hkl[0 0 -1] & {\color{red}-0.08} & -1.15 & {\color{red}-0.08} & 0.04 & -1.66 & -0.19\\ + \hkl[0 0 1] & 0.34 & 0.004 & -2.05 & 0.26 & -1.53 & -0.19\\ + \hkl[0 -1 0] & {\color{orange}-2.39} & -0.17 & {\color{green}-0.10} & {\color{blue}-0.27} & {\color{magenta}-1.88} & {\color{gray}-0.05}\\ + \hkl[0 1 0] & {\color{cyan}-2.25} & -1.90 & {\color{cyan}-2.25} & {\color{purple}-0.12} & {\color{violet}-1.38} & {\color{yellow}-0.06}\\ + \hkl[-1 0 0] & {\color{orange}-2.39} & -0.36 & {\color{cyan}-2.25} & {\color{purple}-0.12} & {\color{magenta}-1.88} & {\color{gray}-0.05}\\ + \hkl[1 0 0] & {\color{cyan}-2.25} & -2.16 & {\color{green}-0.10} & {\color{blue}-0.27} & {\color{violet}-1.38} & {\color{yellow}-0.06}\\ + \hline + C$_{\text{sub}}$ & 0.26 & -0.51 & -0.93 & -0.15 & 0.49 & -0.05\\ + Vacancy & -5.39 ($\rightarrow$ C$_{\text{sub}}$) & -0.59 & -3.14 & -0.54 & -0.50 & -0.31\\ \hline \end{tabular} } - -\vspace*{0.3cm} - -\begin{minipage}{7.0cm} -\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} +\vspace{0.2cm} \begin{center} {\color{blue} - Consisten with initial precipitation model + $E_{\text{b}}$ explainable by stress compensation / increase } \end{center} \end{minipage} +\begin{minipage}{3cm} +\includegraphics[width=3.5cm]{comb_pos.eps} +\end{minipage} \vspace{0.2cm} -\end{slide} - -\begin{slide} - - {\large\bf\boldmath - Combinations of substitutional C and \hkl<1 1 0> Si self-interstitials - } - - \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{minipage}{6.0cm} -\includegraphics[width=5.8cm]{c_sub_si110.ps} +{\bf\boldmath Combinations of \hkl<1 0 0>-type interstitials}\\[0.2cm] +\begin{minipage}[t]{3.2cm} +\underline{\hkl[1 0 0] at position 1}\\[0.1cm] +\includegraphics[width=2.8cm]{00-1dc/2-25.eps} \end{minipage} -\begin{minipage}{7cm} -\scriptsize +\begin{minipage}[t]{3.0cm} +\underline{\hkl[0 -1 0] at position 1}\\[0.1cm] +\includegraphics[width=2.8cm]{00-1dc/2-39.eps} +\end{minipage} +\begin{minipage}[t]{6.1cm} +\vspace{0.7cm} \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 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\\ - $\rightarrow$ low capture radius + \item \ci{} agglomeration energetically favorable + \item Most favorable: C clustering\\ + {\color{red}However \ldots}\\ + \ldots high migration barrier ($>4\,\text{eV}$)\\ + \ldots entropy: + $4\times{\color{cyan}[-2.25]}$ versus + $2\times{\color{orange}[-2.39]}$ \end{itemize} \begin{center} - {\color{blue} - IBS process far from equilibrium\\ - \cs{} \& \si{} instead of thermodynamic ground state - } +{\color{blue}\ci{} agglomeration / no C clustering} \end{center} \end{minipage} -\begin{minipage}{6.5cm} -\includegraphics[width=6.0cm]{162-097.ps} -\begin{itemize} - \item Low migration barrier -\end{itemize} +% insert graph ... +\begin{pspicture}(0,0)(0,0) +\rput(6.5,5.0){\psframebox[fillstyle=solid,opacity=0.5,fillcolor=black]{ +\begin{minipage}{14cm} +\hfill +\vspace{12cm} \end{minipage} -\begin{minipage}{6.5cm} +}} +\rput(6.5,5.3){\rnode{init}{\psframebox[fillstyle=solid,fillcolor=white,linewidth=0.1cm]{ +\begin{minipage}{8cm} \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} -$t=\unit[2900]{fs}$ +\vspace{0.2cm} +\scriptsize +Interaction along \hkl[1 1 0] +\includegraphics[width=7cm]{db_along_110_cc.ps} \end{center} -{\color{blue} -Contribution of entropy to structural formation -} \end{minipage} +}}} +\end{pspicture} \end{slide} +% continue here +\fi + \begin{slide} - {\large\bf\boldmath - Migration in C-Si \hkl<1 0 0> and vacancy combinations - } +{\large\bf + Defect combinations +} - \footnotesize +\footnotesize \vspace{0.1cm} +{\bf Combinations of \ci{} \hkl[0 0 -1] and a vacancy}\\ \begin{minipage}[t]{3cm} \underline{Pos 2, $E_{\text{b}}=-0.59\text{ eV}$}\\ \includegraphics[width=2.8cm]{00-1dc/0-59.eps} \end{minipage} + + + \begin{minipage}[t]{7cm} \vspace{0.2cm} \begin{center} @@ -1724,9 +1775,10 @@ Contribution of entropy to structural formation Without nearby \hkl<1 1 0> Si self-interstitial (IBS)\\ $\Downarrow$\\ {\color{blue}Formation of SiC by successive substitution by C} - \end{center} \end{minipage} + + \begin{minipage}[t]{3cm} \underline{Pos 3, $E_{\text{b}}=-3.14\text{ eV}$}\\ \includegraphics[width=2.8cm]{00-1dc/3-14.eps} @@ -1791,6 +1843,62 @@ Contribution of entropy to structural formation \end{slide} +\end{document} +\ifnum1=0 + +\begin{slide} + + {\large\bf\boldmath + Combinations of substitutional C and \hkl<1 1 0> Si self-interstitials + } + + \scriptsize + +\begin{minipage}{6.0cm} +\includegraphics[width=5.8cm]{c_sub_si110.ps} +\end{minipage} +\begin{minipage}{7cm} +\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 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\\ + $\rightarrow$ 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} + \begin{slide} {\large\bf