X-Git-Url: https://hackdaworld.org/gitweb/?p=lectures%2Flatex.git;a=blobdiff_plain;f=posic%2Fthesis%2Fsic.tex;h=8783989135ac16d7557a50a97290173bb23692a3;hp=c10fe175ee0412ce4241cd5fca699ced06fa12da;hb=2b740e5bda4a90139d952a5efc5345e62747f955;hpb=8254d4d5d47359044bea0b54ebd73f1fe5366d3e

diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex
index c10fe17..8783989 100644
--- a/posic/thesis/sic.tex
+++ b/posic/thesis/sic.tex
@@ -345,13 +345,29 @@ While not being compatible to very-large-scale integration technology, C concent
 \label{section:assumed_prec}
 
 Although high-quality films of single-crystalline 3C-SiC can be produced by means of \ac{IBS} the precipitation mechanism in bulk Si is not yet fully understood.
-Indeed, closely investigating the large amount of literature reveals controversial ideas of SiC formation assumed by the respective authors, which are reviewed in more detail in the following.
+Indeed, closely investigating the large amount of literature reveals controversial ideas of SiC formation, which are reviewed in more detail in the following.
+
+\begin{figure}[ht]
+\begin{center}
+\subfigure[]{\label{fig:sic:hrem:c-si}\includegraphics[width=0.48\columnwidth]{tem_c-si-db.eps}}
+\subfigure[]{\label{fig:sic:hrem:sic}\includegraphics[width=0.48\columnwidth]{tem_3c-sic.eps}}
+\end{center}
+\caption{High resolution transmission electron microscopy (HREM) micrographs\cite{lindner99_2} of agglomerates of C-Si dimers showing dark contrasts and otherwise undisturbed Si lattice fringes (a) and equally sized Moir\'e patterns indicating 3C-SiC precipitates (b).}
+\label{fig:sic:hrem}
+\end{figure}
+
+\ac{HREM} investigations of C-implanted Si at room temperature followed by \ac{RTA} show the formation of C-Si dumbbell agglomerates, which are stable up to annealing temperatures of about \unit[700-800]{$\circ$C}, and a transformation into 3C-SiC precipitates at higher temperatures \cite{werner96,werner97}.
+The precipitates with diamateres between \unit[2]{nm} and \unit[5]{nm} are incorporated in the Si matrix without any remarkable strain fields, which is explained by the nearly equal atomic density of C-Si agglomerates and the SiC unit cell.
+Implantations at \unit[500]{$\circ$C} likewise suggest an initial formation of C-Si dumbbells on regular Si lattice sites, which agglomerate into large clusters \cite{lindner99_2}.
+The agglomerates of such dimers, which do not generate lattice strain but lead to a local increase of the lattice potential \cite{werner96}, are indicated by dark contrasts and otherwise undisturbed Si lattice fringes in \ac{HREM}, as can be seen in Fig.~\ref{fig:sic:hrem:c-si}.
+A topotactic transformation into a 3C-SiC precipitate occurs once a critical radius of \unit[2]{nm} to \unit[4]{nm} is reached.
+The precipitation is manifested by the disappearance of the dark contrasts in favor of Moir\'e patterns (Fig.~\ref{fig:sic:hrem:sic}) due to the lattice mismatch of \unit[20]{\%} of the 3C-SiC precipitate and the Si host.
+The insignificantly lower Si density of SiC of approximately \unit[3]{\%} compared to c-Si results in the emission of only a few excess Si atoms.
 
-\ac{HREM} studies \cite{werner96,werner97,eichhorn99,lindner99_2,koegler03} suggest the formation of C-Si dimers (dumbbells) on regular Si lattice sites, which agglomerate into large clusters indicated by dark contrasts and otherwise undisturbed Si lattice fringes in HREM, as can be seen in Fig.~\ref{fig:hrem:c-si}.
 
-A topotactic transformation into a 3C-SiC precipitate occurs once a critical radius of 2 nm to 4 nm is reached, which is manifested by the disappearance of the dark contrasts in favor of Moir\'e patterns (Fig.~\ref{fig:hrem:sic}) due to the lattice mismatch of \unit[20]{\%} of the 3C-SiC precipitate and c-Si.
+The formation of SiC by a preceeding agglomeration of C-Si dumbbells is supported by studies ... \cite{koegler03,eichhorn99}
+
 
-The insignificantly lower Si density of SiC ($\approx \unit[4]{\%}$) compared to c-Si results in the emission of only a few excess Si atoms.
 
 In contrast, investigations of strained Si$_{1-y}$C$_y$/Si heterostructures formed by MBE\cite{strane94,guedj98}, which incidentally involve the formation of SiC nanocrystallites, suggest an initial coherent precipitation by agglomeration of substitutional instead of interstitial C.
 
@@ -368,18 +384,28 @@ The formation of substitutional C, however, is accompanied by Si self-interstiti
 Both processes are believed to compensate one another.
 
 
-cites:
-
-ibs, c-si agglom: werner96,werner97,eichhorn99,lindner99_2,koegler03
-ibs, c sub: nejim95
-ibs, indicated c sub: martin90 + conclusions reeson8x, eichhorn02
-hetero, coherent sic by sub c: strane94,guedj98
+%cites:
 
-more: taylor93, kitabatake contraction along 110, koegler03
+% continue with strane94 and werner96
 
+%ibs, c-si agglom: werner96,werner97,eichhorn99,lindner99_2,koegler03
+%hetero, coherent sic by sub c: strane94,guedj98
+%ibs, c sub: nejim95
+%ibs, indicated c sub: martin90 + conclusions reeson8x, eichhorn02
+%more: taylor93, kitabatake contraction along 110, koegler03
+%taylor93: sic prec only/more_easy if self interstitials are present
 
 %   -> skorupa 3.2: c sub vs sic prec  
 
+% remember!
+% werner96/7: rt implants followed by rta < 800: C-Si db aggloms | > 800: 3C-SiC
+% taylor93: si_i reduces interfacial energy (explains metastability) of sic/si
+% eichhorn02: high imp temp more efficient than postimp treatment
+
+% todo
+% add sharp iface image!
+
+
 on surface ... md contraction along 110 ... kitabatake ... and ref in lindner ... rheed from si to sic ...
 
 in ibs ... lindner and skorupa ...