From: hackbard Date: Sat, 4 Jun 2011 11:44:27 +0000 (+0200) Subject: added si functions X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1925edda48f239477644a6cbcd7c3c728405130b;p=lectures%2Flatex.git added si functions --- diff --git a/posic/thesis/md.tex b/posic/thesis/md.tex index 963edd5..f3689eb 100644 --- a/posic/thesis/md.tex +++ b/posic/thesis/md.tex @@ -364,7 +364,8 @@ The \ci{} \hkl<1 0 0> DB dominated struture turns into a structure characterized Clearly, the high-temperature results indicate the precipitation mechanism involving an increased participation of \cs. Although diamond and graphite like bonds are reduced, no agglomeration of C is observed within the simulated time. Isolated structures of stretched SiC, which are adjusted to the c-Si host with respect to the lattice constant and alignement, are formed. -It would be conceivable that by agglomeration of further \cs{} atoms the interfacial energy could be overcome and a transition from a coherent and stretched SiC structure into an incoherent and partially strain-compensated SiC precipitate could occur. +By agglomeration of \cs{} the interfacial energy could be overcome and a transition from a coherent and stretched SiC structure into an incoherent and partially strain-compensated SiC precipitate could occur. +Indeed, \si in the near surrounding is observed, which may initially compensate tensile strain in the stretched SiC structure or rearrange the \cs{} sublattice and finally serve as supply for additional C to form further SiC or compensate strain at the interface of the incoherent SiC precipitate and the Si host. \subsection{High C concentration simulations} @@ -502,8 +503,8 @@ Thus, elevated temperatures are considered to constitute a necessary condition t It is concluded that precipitation occurs by successive agglomeration of C$_{\text{s}}$ as already proposed by Nejim et~al.~\cite{nejim95}. This agrees well with previous results of the {\em ab initio} study on defects in C implanted Si, which show C$_{\text{s}}$ to occur in all probability. However, agglomeration and rearrangement is enabled by mobile C$_{\text{i}}$, which has to be present at the same time and is formed by recombination of C$_{\text{s}}$ and Si$_{\text{i}}$. +Indeed, \si{} is observed in the direct surrounding of the stretched SiC structures. +Next to the rearrangement, \si{} is required as a supply for additional C atoms to form further SiC and to compensate strain, either within the coherent and stretched SiC structure as well as at the interface of the incoherent SiC precipitate and the Si host. In contrast to assumptions of an abrupt precipitation of an agglomerate of C$_{\text{i}}$ \cite{werner96,werner97,eichhorn99,lindner99_2,koegler03}, however, structural evolution is believed to occur by a successive occupation of usual Si lattice sites with substitutional C. This mechanism satisfies the experimentally observed alignment of the \hkl(h k l) planes of the precipitate and the substrate, whereas there is no obvious reason for the topotactic orientation of an agglomerate consisting exclusively of C-Si dimers, which would necessarily involve a much more profound change in structure for the transition into SiC. -{\color{red}Si serves as vehicle, for stress compensation (vorallem stress, evtl auch schon vorher rausarbeiten!) and as Si supply for further SiC.} -