From: hackbard Date: Thu, 5 Jan 2012 23:18:21 +0000 (+0100) Subject: knapp, aber koennte gehen X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bb741b8e0c861ccd0f8751734fa967691665de9a;p=lectures%2Flatex.git knapp, aber koennte gehen --- diff --git a/posic/talks/defense.tex b/posic/talks/defense.tex index 209fbd7..e0f334d 100644 --- a/posic/talks/defense.tex +++ b/posic/talks/defense.tex @@ -1708,8 +1708,7 @@ $\Rightarrow$ Phase transition consists of {\color{red}\underline{many}} {\bf Limitations related to the short range potential}\\[0.2cm] Cut-off function limits interaction to next neighbours\\ -$\Rightarrow$ Overestimated unphysical high forces of next neighbours - (factor: 2.4--3.4) +$\Rightarrow$ Overestimated diffusion barrier (factor: 2.4--3.4) \vspace{1.4cm} @@ -2013,7 +2012,7 @@ High C \& low T implants \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 Increased participation of \cs{} in the precipitation process + \item \cs{} involved in the precipitation process at elevated temperatures \item \si{}: vehicle to form \cs{} \& supply of Si \& stress compensation (stretched SiC, interface) \end{itemize} @@ -2022,7 +2021,7 @@ High C \& low T implants \begin{center} {\color{blue}\bf -\framebox{Precipitation by successive agglomeration of \cs{}} +\framebox{IBS: 3C-SiC precipitation occurs by successive agglomeration of \cs{}} } \end{center} diff --git a/posic/talks/defense.txt b/posic/talks/defense.txt index 7ffca51..6a01079 100644 --- a/posic/talks/defense.txt +++ b/posic/talks/defense.txt @@ -377,10 +377,10 @@ even the C atoms are already found in a separation as expected in cubic SiC. turning to the high C concentration simulations, i.e. the v1 and v2 simulation, a high amount of strongly bound C-C bonds -as in graphite or diamond are observed. -an increased defect and damage density is obtained, -which makes it hard to categorize and trace defect arrangements. -only short range orde is observed. +as in graphite or diamond is observed. +due to increased defect and damage densities +defect arrangemnets are hard to categorize and trace. +only short range order is observed. and, indeed, comparing to other distribution data, an amorphous SiC-like phase is obtained. @@ -447,10 +447,8 @@ slide 26 to conclude, stretched coherent structures of SiC embedded in the Si host are directly observed. -therefore, an increased participation of Cs is suggested -for implantations at elevated temperatures, -which simulate the conditions prevalent in ibs that deviate the system -from thermodynamic equilibrium enabling Ci to turn into Cs. +therefore, it is concluded that Cs is extensively involved +in the precipitation process for implantations at elevated temperatures. the emission of Si_i serves several needs: as a vehicle to rearrange the Cs, @@ -470,10 +468,32 @@ to summarize, the results suggest that Cs plays an important role in the precipitation process. moreover, high temperatures are necessary to model ibs conditions, which are far from equilibrium. +the high temperatures deviate the system from thermodynamic equilibrium +enabling Ci to turn into Cs. slide 27 to summarize and conclude ... +defect structures were described by both methods. +the interstitial carbon mmigration path was identified. +it turned out that the the diffusion barrier is drastically overestimated +within the ea description. + +combinations of defects were investigated by first principles methods. +the agglomeration of point defects is energetically favorable. +however, substitutional carbon arises in all probability. +even transitions from the ground state are very likely to occur. + +concerning the precipitation simulations, the problem of the potential +enhanced slow phase space propagation was discussed. +it was found that low and high temperatures result in structures +dominated by interstitial and substitutional defects respectively. +comparing with experiment, it is concluded, +that high temperatures are necessary to model ibs conditions. +it was concluded that Cs is involved in the precipitation process +at elevated temperatures. +the role of the Si_i was outlined and in one case directly observed +in simulation. slide 28