X-Git-Url: https://hackdaworld.org/gitweb/?p=lectures%2Flatex.git;a=blobdiff_plain;f=posic%2Ftalks%2Femrs2012.tex;fp=posic%2Ftalks%2Femrs2012.tex;h=c23a8a52e8e522c40503dafcef942db7a10fedba;hp=ee03191b08b9060a5f97f871012a04be63c9e1f4;hb=147329059cdda2ebf293426b7fdbcd13b0c783f9;hpb=f0ac0a8402afa79a6a06b9841db95bcfaf670303 diff --git a/posic/talks/emrs2012.tex b/posic/talks/emrs2012.tex index ee03191..c23a8a5 100644 --- a/posic/talks/emrs2012.tex +++ b/posic/talks/emrs2012.tex @@ -1272,7 +1272,7 @@ Summary \begin{itemize} \item First-principles investigation of defect combinations and mobilities in Si - \item Empirical potential MD simulations on SiC prcipitation in Si + \item Empirical potential MD simulations on SiC precipitation in Si \end{itemize} \vspace{0.2cm} @@ -1359,8 +1359,6 @@ Further conclusions -\ifnum1=0 - \begin{slide} \headphd @@ -1414,6 +1412,74 @@ Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\ \begin{slide} +\headphd +{\large\bf + IBS 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] + Low remaining amount of 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}{6.9cm} +\includegraphics[width=7cm]{ibs_3c-sic.eps}\\[-0.4cm] +\begin{center} +{\tiny + XTEM: single crystalline 3C-SiC in Si\hkl(1 0 0) +} +\end{center} +\end{minipage} +\begin{minipage}{5cm} +\begin{center} +\begin{pspicture}(0,0)(0,0) +\rnode{box}{ +\psframebox[fillstyle=solid,fillcolor=white,linecolor=blue,linestyle=solid]{ +\begin{minipage}{3.3cm} + \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(-5.3,5.5){\pnode{h0}} +\rput(-1.95,5.5){\pnode{h1}} +\ncline[linecolor=blue]{-}{h0}{h1} +\ncline[linecolor=blue]{->}{h1}{box} +\end{pspicture} +\end{center} +\end{minipage} + +\end{slide} + +\begin{slide} + \footnotesize \headphd @@ -1619,6 +1685,248 @@ $\Rightarrow$ $sp^2$ hybridization \end{slide} +\begin{slide} + +\headphd +{\large\bf\boldmath + C interstitial migration --- ab initio +} + +\scriptsize + +\vspace{0.3cm} + +\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}{0.2cm} +$\rightarrow$ +\end{minipage} +\begin{minipage}{2.0cm} +\includegraphics[width=2.0cm]{c_pd_vasp/bc_2333.eps} +\end{minipage} +\begin{minipage}{0.2cm} +$\rightarrow$ +\end{minipage} +\begin{minipage}{2.0cm} +\includegraphics[width=2.0cm]{c_pd_vasp/100_next_2333.eps} +\end{minipage}\\[0.1cm] +Symmetry:\\ +$\Rightarrow$ Sufficient to consider \hkl[00-1] to BC transition\\ +$\Rightarrow$ 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}\\[0.4cm] +%\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}{0.2cm} +$\rightarrow$ +\end{minipage} +\begin{minipage}{2.0cm} +\includegraphics[width=2.0cm]{c_pd_vasp/00-1-0-10_2333.eps} +\end{minipage} +\begin{minipage}{0.2cm} +$\rightarrow$ +\end{minipage} +\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} + +\headphd +{\large\bf\boldmath + C interstitial migration --- analytical potential +} +\scriptsize + +\vspace{0.3cm} + +\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 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} +\begin{minipage}[t]{0.2cm} +\hfill +\end{minipage} +\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 Minimum 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{red}\bf Drastically overestimated diffusion barrier} +\end{center} + +\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} + +\headphd +{\large\bf\boldmath + Silicon carbide precipitation simulations at \degc{450} as in IBS +} + +\small + +\begin{minipage}{6.3cm} +\hspace*{-0.4cm}\includegraphics[width=6.5cm]{sic_prec_450_si-c.ps}\\ +\hspace*{-0.4cm}\includegraphics[width=6.5cm]{sic_prec_450_si-si_c-c.ps} +\hfill +\end{minipage} +\begin{minipage}{6.1cm} +\scriptsize +\underline{Low C concentration --- {\color{red}$V_1$}}\\[0.1cm] +\ci{} \hkl<1 0 0> dumbbell dominated structure +\begin{itemize} + \item Si-C bumbs around \unit[0.19]{nm} + \item C-C peak at \unit[0.31]{nm} (expected in 3C-SiC):\\ + concatenated differently oriented \ci{} DBs + \item Si-Si NN distance stretched to \unit[0.3]{nm} +\end{itemize} +\begin{pspicture}(0,0)(6.0,1.0) +\rput(3.2,0.5){\psframebox[linewidth=0.03cm,linecolor=blue]{ +\begin{minipage}{6cm} +\centering +Formation of \ci{} dumbbells\\ +C atoms separated as expected in 3C-SiC +\end{minipage} +}} +\end{pspicture}\\[0.1cm] +\underline{High C concentration --- {\color{green}$V_2$}/{\color{blue}$V_3$}} +\begin{itemize} +\item High amount of strongly bound C-C bonds +\item Increased defect \& damage density\\ + $\rightarrow$ Arrangements hard to categorize and trace +\item Only short range order observable +\end{itemize} +\begin{pspicture}(0,0)(6.0,0.8) +\rput(3.2,0.5){\psframebox[linewidth=0.03cm,linecolor=blue]{ +\begin{minipage}{6cm} +\centering +Amorphous SiC-like phase +\end{minipage} +}} +\end{pspicture}\\[0.3cm] +\begin{pspicture}(0,0)(6.0,2.0) +\rput(3.2,1.0){\psframebox[linewidth=0.05cm,linecolor=black]{ +\begin{minipage}{6cm} +\vspace{0.1cm} +\centering +{\bf\color{red}Formation of 3C-SiC fails to appear}\\[0.3cm] +\begin{minipage}{0.8cm} +{\bf\boldmath $V_1$:} +\end{minipage} +\begin{minipage}{5.1cm} +Formation of \ci{} indeed occurs\\ +Agllomeration not observed +\end{minipage}\\[0.3cm] +\begin{minipage}{0.8cm} +{\bf\boldmath $V_{2,3}$:} +\end{minipage} +\begin{minipage}{5.1cm} +Amorphous SiC-like structure\\ +(not expected at \degc{450})\\[0.05cm] +No rearrangement/transition into 3C-SiC +\end{minipage}\\[0.1cm] +\end{minipage} +}} +\end{pspicture} +\end{minipage} + +\end{slide} + +\begin{slide} + +\headphd +{\large\bf\boldmath + Increased temperature simulations --- $V_1$ +} + +\small + +\begin{minipage}{6.2cm} +\hspace*{-0.4cm}\includegraphics[width=6.5cm]{tot_pc_thesis.ps} +\hfill +\end{minipage} +\begin{minipage}{6.2cm} +\includegraphics[width=6.5cm]{tot_pc3_thesis.ps} +\end{minipage} + +\begin{minipage}{6.2cm} +\hspace*{-0.4cm}\includegraphics[width=6.5cm]{tot_pc2_thesis.ps} +\hfill +\end{minipage} +\begin{minipage}{6.3cm} +\scriptsize + \underline{Si-C bonds:} + \begin{itemize} + \item Vanishing cut-off artifact (above $1650\,^{\circ}\mathrm{C}$) + \item Structural change: \ci{} \hkl<1 0 0> DB $\rightarrow$ + {\color{blue}\cs{}} + \end{itemize} + \underline{Si-Si bonds:} + {\color{blue}Si-C$_{\text{sub}}$-Si} along \hkl<1 1 0> + ($\rightarrow$ 0.325 nm)\\[0.1cm] + \underline{C-C bonds:} + \begin{itemize} + \item C-C next neighbour pairs reduced (mandatory) + \item Peak at 0.3 nm slightly shifted\\[0.05cm] + $\searrow$ \ci{} combinations (dashed arrows)\\ + $\nearrow$ \ci{} \hkl<1 0 0> \& {\color{blue}\cs{} combinations} (|)\\ + $\nearrow$ \ci{} pure \cs{} combinations ($\downarrow$)\\[0.05cm] + Range [|-$\downarrow$]: {\color{blue}\cs{} \& \cs{} with nearby \si} + \end{itemize} +\end{minipage} + +\end{slide} + \begin{slide} {\large\bf @@ -1687,82 +1995,6 @@ High C \& low T implants \end{slide} - - -\begin{slide} - - {\large\bf - Valuation of a practicable temperature limit - } - - \small - -\vspace{0.1cm} - -\begin{center} -\framebox{ -{\color{blue} -Recrystallization is a hard task! -$\Rightarrow$ Avoid melting! -} -} -\end{center} - -\vspace{0.1cm} - -\footnotesize - -\begin{minipage}{6.4cm} -\includegraphics[width=6.4cm]{fe_and_t.ps} -\end{minipage} -\begin{minipage}{5.7cm} -\underline{Melting does not occur instantly after}\\ -\underline{exceeding the melting point $T_{\text{m}}=2450\text{ K}$} -\begin{itemize} -\item required transition enthalpy -\item hysterisis behaviour -\end{itemize} -\underline{Heating up c-Si by 1 K/ps} -\begin{itemize} -\item transition occurs at $\approx$ 3125 K -\item $\Delta E=0.58\text{ eV/atom}=55.7\text{ kJ/mole}$\\ - (literature: 50.2 kJ/mole) -\end{itemize} -\end{minipage} - -\vspace{0.1cm} - -\framebox{ -\begin{minipage}{4cm} -Initially chosen temperatures:\\ -$1.0 - 1.2 \cdot T_{\text{m}}$ -\end{minipage} -} -\begin{minipage}{2cm} -\begin{center} -$\Longrightarrow$ -\end{center} -\end{minipage} -\framebox{ -\begin{minipage}{5cm} -Introduced C (defects)\\ -$\rightarrow$ reduction of transition point\\ -$\rightarrow$ melting already at $T_{\text{m}}$ -\end{minipage} -} - -\vspace{0.4cm} - -\begin{center} -\framebox{ -{\color{blue} -Maximum temperature used: $0.95\cdot T_{\text{m}}$ -} -} -\end{center} - -\end{slide} - \begin{slide} {\large\bf @@ -2036,7 +2268,5 @@ Defect formation energy with respect to the size of the supercell\\[0.1cm] \end{slide} -\fi - \end{document}