new stuff ... hopefully ibs chapter can be finished soon!

diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex
index 9a7cc44cf9d275db6351dbb870c0d44e803d0eab..146e7241f28a46b6075c9cb02b829d0b8e7a3f7f 100644 (file)
--- a/posic/thesis/sic.tex
+++ b/posic/thesis/sic.tex
@@ -239,15 +239,25 @@ Indeed, for the first time, buried homogeneous and stoichiometric epitaxial 3C-S
 The necessity of the applied extreme temperature and time scale is attributed to the stability of substitutional C within the Si matrix being responsible for high activation energies necessary to dissolve such precipitates and, thus, allow for redistribution of the implanted C atoms.
 In order to avoid extreme annealing temperatures close to the melting temperature of Si, triple-energy implantations in the range from \unit[180-190]{keV} with stoichiometric doses at a constant target temperature of \unit[860]{$^{\circ}$C} achieved by external substrate heating were performed \cite{martin90}.
 It was shown that a thick buried layer of SiC is directly formed during implantation, which consists of small, only slightly misorientated but severely twinned 3C-SiC crystallites.
-The authors assumed that due to the auxiliary heating rather than ion beam heating as employed in all the preceding studies, the complexity of the remaining defects in the synthsized structure is fairly reduced.
+The authors assumed that due to the auxiliary heating rather than ion beam heating as employed in all the preceding studies, the complexity of the remaining defects in the synthesized structure is fairly reduced.
+Even better qualities by direct synthesis were obtained for implantations at \unit[950]{$^{\circ}$C} \cite{nejim95}.
 Since no amorphous or polycrystalline regions have been identified, twinning is considered to constitute the main limiting factor in the \ac{IBS} of SiC.
-... maybe nejim?!?
-... lindner limit in dose -> 1250
+
+Further studies revealed the possibility to form buried layers of SiC by IBS at moderate substrate and anneal temperatures \cite{lindner95}.
+Different doses of C ions with an energy of \unit[180]{keV} were implanted at \unit[330-440]{$^{\circ}$C} and annealed at \unit[1200]{$^{\circ}$C} or \unit[1250]{$^{\circ}$C} for \unit[5-10]{h}.
+For a critical dose, which was found to depend on the orientation of the Si substrate, corresponding to a \unit[50]{at.\%} C concentration at the implantation peak, C atoms get redistributed appropriately resulting in the formation of a stoichiometric buried layer of SiC exhibiting a well-defined interface to the Si host matrix.
+Redistribution is hindered for overstoichiometric doses ... and higher implantation energies resulting in randomly distributed SiC precipitates ...
+
+high t -> direct SiC formation -> no redistribution ...
+
+..  lindner limit in dose -> 1250
 ... two temp implantation ... sharp interface
 By understanding some basic processes (32-36), \ac{IBS} nowadays has become a promising method to form thin SiC layers of high quality exclusively of the 3C polytype embedded in and epitactically aligned to the Si host featuring a sharp interface \cite{lindner99,lindner01,lindner02}.
 
 \section{Substoichiometric concentrations of carbon in crystalline silicon}
 
+diffusion mechanism, lattice distortion, hmm ... extra section needed?
+
 \section{Assumed cubic silicon carbide conversion mechanisms}
 \label{section:assumed_prec}
 
@@ -256,4 +266,8 @@ on surface ... md contraction along 110 ... kitabatake ... and ref in lindner ..
 in ibs ... lindner and skorupa ...
 
 nejim however ...
+  high temps -> good alignment with substrate
+  C occupies predominantly substitutional lattice sites
+  also indictaed by other direct synthesis experiments like martin90 and conclusions of reeson8X ...
 
+eichhornXX, koegler, lindner ...