From: hackbard Date: Tue, 9 Aug 2011 21:48:00 +0000 (+0200) Subject: better link to chapter 7 (part 1) X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a92e4a0754dced3ea2764012a7b521cbad02856a;p=lectures%2Flatex.git better link to chapter 7 (part 1) --- diff --git a/posic/thesis/defects.tex b/posic/thesis/defects.tex index ab8bd72..dc62e5f 100644 --- a/posic/thesis/defects.tex +++ b/posic/thesis/defects.tex @@ -3,7 +3,7 @@ Regarding the supposed conversion mechanisms of SiC in c-Si as introduced in section \ref{section:assumed_prec} the understanding of C and Si interstitial point defects in c-Si is of fundamental interest. During implantation, defects such as vacancies (V), substitutional C (C$_{\text{s}}$), interstitial C (C$_{\text{i}}$) and Si self-interstitials (Si$_{\text{i}}$) are created, which are believed to play a decisive role in the precipitation process. -In the following, these defects are systematically examined by computationally efficient, classical potential as well as highly accurate DFT calculations with the parameters and simulation conditions that are defined in chapter \ref{chapter:simulation}. +In the following, these defects are systematically examined by computationally efficient, classical potential as well as highly accurate DFT calculations with the parameters and simulation conditions that are defined in chapter~\ref{chapter:simulation}. Both methods are used to investigate selected diffusion processes of some of the defect configurations. While the quantum-mechanical description yields results that excellently compare to experimental findings, shortcomings of the classical potential approach are identified. These shortcomings are further investigated and the basis for a workaround, as proposed later on in the classical MD simulation chapter, is discussed. @@ -1658,7 +1658,8 @@ Thus, elevated temperatures might lead to thermodynamically unstable configurati % todo - sync with conclusion chapter -These findings allow to draw conclusions on the mechanisms involved in the process of SiC conversion in Si, which is elaborated in more detail within the comprehensive description in chapter~\ref{chapter:summary}. +These findings allow to draw conclusions on the mechanisms involved in the process of SiC conversion in Si. +% which is elaborated in more detail within the comprehensive description in chapter~\ref{chapter:summary}. Agglomeration of C$_{\text{i}}$ is energetically favored and enabled by a low activation energy for migration. Although ion implantation is a process far from thermodynamic equilibrium, which might result in phases not described by the Si/C phase diagram, i.e. a C phase in Si, high activation energies are believed to be responsible for a low probability of the formation of C-C clusters. @@ -1684,6 +1685,8 @@ In both cases Si$_{\text{i}}$ might be attributed a third role, which is the par Furthermore, the experimentally observed alignment of the \hkl(h k l) planes of the precipitate and the substrate is satisfied by the mechanism of successive positioning of C$_{\text{s}}$. In contrast, 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. +Conclusions on the SiC precipitation mechanism in Si, which additionally include and consider results of the molecular dynamics investigations presented in the following, are elaborated in more detail within the comprehensive description in chapter~\ref{chapter:summary}. + %Prevailing conditions in the IBS process at elevated temperatures and the fact that IBS is a nonequilibrium process reinforce the possibility of formation of substitutional C instead of the thermodynamically stable C-Si dumbbell interstitials predicted by simulations at zero Kelvin. \label{section:defects:noneq_process_02}