X-Git-Url: https://hackdaworld.org/gitweb/?p=lectures%2Flatex.git;a=blobdiff_plain;f=posic%2Ftalks%2Fdefense.tex;h=2ae5461209d75b91dc221065859efd36b3ac678e;hp=bfd92d02b17584803e5572eb17ac4fe9f45a1131;hb=e3b7278cc861f9eda107e72ebd8f07f90056c3a8;hpb=b72d5fabe9b016843d069c4478310ea67e76fc47 diff --git a/posic/talks/defense.tex b/posic/talks/defense.tex index bfd92d0..2ae5461 100644 --- a/posic/talks/defense.tex +++ b/posic/talks/defense.tex @@ -246,61 +246,9 @@ E\\ \end{slide} -% motivation - -\begin{slide} - -\headphd - {\large\bf - Polytypes of SiC\\[0.6cm] - } - -\vspace{0.6cm} - -\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} - -\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 - & 3C-SiC & 4H-SiC & 6H-SiC & Si & GaN & Diamond\\ -\hline -Hardness [Mohs] & \multicolumn{3}{c}{------ 9.6 ------}& 6.5 & - & 10 \\ -Band gap [eV] & 2.36 & 3.23 & 3.03 & 1.12 & 3.39 & 5.5 \\ -Break down field [$10^6$ V/cm] & 4 & 3 & 3.2 & 0.6 & 5 & 10 \\ -Saturation drift velocity [$10^7$ cm/s] & 2.5 & 2.0 & 2.0 & 1 & 2.7 & 2.7 \\ -Electron mobility [cm$^2$/Vs] & 800 & 900 & 400 & 1100 & 900 & 2200 \\ -Hole mobility [cm$^2$/Vs] & 320 & 120 & 90 & 420 & 150 & 1600 \\ -Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\ -\hline -\end{tabular} - -\begin{pspicture}(0,0)(0,0) -\psellipse[linecolor=green](5.7,2.05)(0.4,0.50) -\end{pspicture} -\begin{pspicture}(0,0)(0,0) -\psellipse[linecolor=green](5.6,0.89)(0.4,0.20) -\end{pspicture} -\begin{pspicture}(0,0)(0,0) -\psellipse[linecolor=red](10.45,0.42)(0.4,0.20) -\end{pspicture} - -\end{slide} - % fabrication +\ifnum1=0 \begin{slide} \headphd @@ -335,15 +283,15 @@ SiC thin films by MBE \& CVD \vspace{-0.5cm} -\begin{center} -\color{red} -\framebox{ -{\footnotesize\color{black} - Mismatch in \underline{thermal expansion coeefficient} - and \underline{lattice parameter} w.r.t. substrate -} -} -\end{center} +%\begin{center} +%\color{red} +%\framebox{ +%{\footnotesize\color{black} +% Mismatch in \underline{thermal expansion coeefficient} +% and \underline{lattice parameter} w.r.t. substrate +%} +%} +%\end{center} \vspace{0.1cm} @@ -373,17 +321,27 @@ Ion beam synthesis (IBS) of burried 3C-SiC layers in Si\hkl(1 0 0) \end{minipage} } \begin{minipage}{5.5cm} -\begin{center} -{\footnotesize -No surface bending effects\\ -High areal homogenity\\[0.1cm] -$\Downarrow$\\[0.1cm] -Synthesis of large area SiC films possible -} -\end{center} + \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{center} \end{minipage} +%\begin{minipage}{5.5cm} +%\begin{center} +%{\footnotesize +%No surface bending effects\\ +%High areal homogenity\\[0.1cm] +%$\Downarrow$\\[0.1cm] +%Synthesis of large area SiC films possible +%} +%\end{center} +%\end{minipage} + \end{slide} +\fi \begin{slide} @@ -403,7 +361,7 @@ Synthesis of large area SiC films possible $\Rightarrow$ Epitaxial {\color{blue}3C-SiC} layer \& {\color{blue}precipitates} \item \underline{Implantation step 2}\\[0.1cm] - Little remaining dose | \unit[180]{keV} | \degc{250}\\ + Low remaining amount of dose | \unit[180]{keV} | \degc{250}\\ $\Rightarrow$ Destruction/Amorphization of precipitates at layer interface \item \underline{Annealing}\\[0.1cm] @@ -451,8 +409,6 @@ Synthesis of large area SiC films possible \end{slide} -% contents - \begin{slide} \headphd @@ -682,7 +638,7 @@ r = \unit[2--4]{nm} \begin{itemize} \item High-temperature implantation {\tiny\color{gray}/Nejim~et~al./} \begin{itemize} - \item C incorporated {\color{blue}substitutionally} on regular Si lattice sites + \item {\color{blue}Substitutionally} incorporated C on regular Si lattice sites \item \si{} reacting with further C in cleared volume \end{itemize} \item Annealing behavior {\tiny\color{gray}/Serre~et~al./} @@ -692,10 +648,10 @@ r = \unit[2--4]{nm} \end{itemize} $\Rightarrow$ mobile {\color{red}\ci} opposed to stable {\color{blue}\cs{}} configurations -\item Strained silicon \& Si/SiC heterostructures +\item Strained silicon \& Si$_{1-y}$C$_y$ heterostructures {\tiny\color{gray}/Strane~et~al./Guedj~et~al./} \begin{itemize} - \item {\color{blue}Coherent} SiC precipitates (tensile strain) + \item Initial {\color{blue}coherent} SiC precipitates (tensile strain) \item Incoherent SiC (strain relaxation) \end{itemize} \end{itemize} @@ -714,6 +670,8 @@ r = \unit[2--4]{nm} \begin{slide} +% contents + \headphd {\large\bf Outline @@ -1215,7 +1173,7 @@ $\Rightarrow$ $sp^2$ hybridization \scriptsize -\vspace{0.1cm} +\vspace{0.2cm} \begin{minipage}{6.8cm} \framebox{\hkl[0 0 -1] $\rightarrow$ \hkl[0 0 1]}\\ @@ -1240,7 +1198,8 @@ $\Rightarrow$ 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] +%\end{minipage}\\[0.2cm] +\end{minipage}\\[0.3cm] %\hrule % \begin{minipage}{6.8cm} @@ -1268,9 +1227,9 @@ Note: Change in orientation \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} +%\begin{center} +%Reorientation pathway composed of two consecutive processes of the above type +%\end{center} \end{slide} @@ -2224,10 +2183,12 @@ High C \& low T implants \headphd {\large\bf - Summary / Conclusions + Summary and Conclusions } -\scriptsize +\footnotesize + +\vspace{0.1cm} \framebox{ \begin{minipage}{12.3cm} @@ -2237,19 +2198,12 @@ High C \& low T implants \begin{itemize} \item Point defects excellently / fairly well described by DFT / EA - \item C$_{\text{sub}}$ drastically underestimated by EA - \item EA predicts correct ground state: - C$_{\text{sub}}$ \& \si{} $>$ \ci{} - \item Identified migration path explaining - diffusion and reorientation experiments by DFT - \item EA fails to describe \ci{} migration: - Wrong path \& overestimated barrier + \item Identified \ci{} migration path + \item EA drastically overestimates the diffusion barrier \end{itemize} \item Combinations of defects \begin{itemize} \item Agglomeration of point defects energetically favorable - by compensation of stress - \item Formation of C-C unlikely \item C$_{\text{sub}}$ favored conditions (conceivable in IBS) \item \ci{} \hkl<1 0 0> $\leftrightarrow$ \cs{} \& \si{} \hkl<1 1 0>\\ Low barrier (\unit[0.77]{eV}) \& low capture radius @@ -2262,12 +2216,11 @@ High C \& low T implants \begin{minipage}[t]{12.3cm} \underline{Pecipitation simulations} \begin{itemize} - \item High C concentration $\rightarrow$ amorphous SiC like phase \item Problem of potential enhanced slow phase space propagation \item Low T $\rightarrow$ C-Si \hkl<1 0 0> dumbbell dominated structure \item High T $\rightarrow$ C$_{\text{sub}}$ dominated structure \item High T necessary to simulate IBS conditions (far from equilibrium) - \item Precipitation by successive agglomeration of \cs (epitaxy) + \item Increased participation of \cs{} in the precipitation process \item \si{}: vehicle to form \cs{} \& supply of Si \& stress compensation (stretched SiC, interface) \end{itemize} @@ -2275,7 +2228,7 @@ High C \& low T implants } \begin{center} -{\color{blue} +{\color{blue}\bf \framebox{Precipitation by successive agglomeration of \cs{}} } \end{center} @@ -2284,9 +2237,10 @@ High C \& low T implants \begin{slide} - {\large\bf - Acknowledgements - } +\headphd +{\large\bf + Acknowledgements +} \vspace{0.1cm} @@ -2296,39 +2250,87 @@ High C \& low T implants \underline{Augsburg} \begin{itemize} - \item Prof. B. Stritzker (accomodation at EP \RM{4}) - \item Ralf Utermann (EDV) - \end{itemize} - - \underline{Berlin/Brandenburg} - \begin{itemize} - \item PD Volker Eyert (Ref) + \item Prof. B. Stritzker + \item Ralf Utermann \end{itemize} \underline{Helsinki} \begin{itemize} - \item Prof. K. Nordlund (MD) + \item Prof. K. Nordlund \end{itemize} \underline{Munich} \begin{itemize} - \item Bayerische Forschungsstiftung (financial support) + \item Bayerische Forschungsstiftung \end{itemize} \underline{Paderborn} \begin{itemize} - \item Prof. J. Lindner (SiC) - \item Prof. G. Schmidt (DFT + financial support) - \item Dr. E. Rauls (DFT + SiC) + \item Prof. J. Lindner + \item Prof. G. Schmidt + \item Dr. E. Rauls \end{itemize} +\vspace{ 0.2cm} + \begin{center} \framebox{ -\bf Thank you for your attention! +\normalsize\bf Thank you for your attention! } \end{center} \end{slide} +\begin{slide} + +\headphd + {\large\bf + Polytypes of SiC\\[0.6cm] + } + +\vspace{0.6cm} + +\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} + +\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 + & 3C-SiC & 4H-SiC & 6H-SiC & Si & GaN & Diamond\\ +\hline +Hardness [Mohs] & \multicolumn{3}{c}{------ 9.6 ------}& 6.5 & - & 10 \\ +Band gap [eV] & 2.36 & 3.23 & 3.03 & 1.12 & 3.39 & 5.5 \\ +Break down field [$10^6$ V/cm] & 4 & 3 & 3.2 & 0.6 & 5 & 10 \\ +Saturation drift velocity [$10^7$ cm/s] & 2.5 & 2.0 & 2.0 & 1 & 2.7 & 2.7 \\ +Electron mobility [cm$^2$/Vs] & 800 & 900 & 400 & 1100 & 900 & 2200 \\ +Hole mobility [cm$^2$/Vs] & 320 & 120 & 90 & 420 & 150 & 1600 \\ +Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\ +\hline +\end{tabular} + +\begin{pspicture}(0,0)(0,0) +\psellipse[linecolor=green](5.7,2.05)(0.4,0.50) +\end{pspicture} +\begin{pspicture}(0,0)(0,0) +\psellipse[linecolor=green](5.6,0.89)(0.4,0.20) +\end{pspicture} +\begin{pspicture}(0,0)(0,0) +\psellipse[linecolor=red](10.45,0.42)(0.4,0.20) +\end{pspicture} + +\end{slide} + \end{document}