X-Git-Url: https://hackdaworld.org/gitweb/?a=blobdiff_plain;f=posic%2Fthesis%2Fsic.tex;h=abcdd3e0a48ed8cdd2b6fb5b9c7ffd864e66e93b;hb=0b8f9b2a929b9b3b1d21bca4288dd813258786ed;hp=dd18103cda2349e07577e270ccfaf86423f0a892;hpb=609e8910dde4adea6d71f9083362ef0bc109d340;p=lectures%2Flatex.git

diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex
index dd18103..abcdd3e 100644
--- a/posic/thesis/sic.tex
+++ b/posic/thesis/sic.tex
@@ -168,13 +168,23 @@ During carbonization the Si surface is chemically converted into a SiC film with
 In a next step, the epitaxial deposition of SiC is realized by an additional supply of Si atoms at similar temperatures.
 Low defect densities in the buffer layer are a prerequisite for obtaining good quality SiC layers during growth, although defect densities decrease with increasing distance of the SiC/Si interface \cite{shibahara86}.
 Next to surface morphology defects such as pits and islands, the main defects in 3C-SiC heteroepitaxial layers are twins, stacking faults (SF) and antiphase boundaries (APB) \cite{shibahara86,pirouz87}.
+APB defects, which constitute the primary residual defects in thick layers, are formed near surface terraces that differ in a single-atom-height step resulting in domains of SiC separated by a boundary, which consists of either Si-Si or C-C bonds due to missing or disturbed sublattice information \cite{desjardins96,kitabatake97}.
+However, the number of such defects can be reduced by off-axis growth on a Si \hkl(0 0 1) substrate miscut towards \hkl[1 1 0] by \unit[2]{$^{\circ}$}-\unit[4]{$^{\circ}$} \cite{shibahara86,powell87_2}.
+This results in the thermodynamically favored growth of a single phase due to the uni-directional contraction of Si-C-Si bond chains perpendicular to the terrace steps edges during carbonization and the fast growth parallel to the terrace edges during growth under Si rich conditions \cite{kitabatake97}.
+By MBE, lower process temperatures than these typically employed in CVD have been realized \cite{hatayama95,henke95,fuyuki97,takaoka98}, which is essential for limiting thermal stresses and to avoid resulting substrate bending, a key issue in obtaining large area 3C-SiC surfaces.
+In summary, the almost universal use of Si has allowed significant progress in the understanding of heteroepitaxial growth of SiC on Si.
+However, mismatches in the thermal expansion coefficient and the lattice parameter cause a considerably high concentration of various defects, which is responsible for structural and electrical qualities that are not yet statisfactory.
+
+The alternative attempt to grow SiC on SiC substrates has shown to drastically reduce the concentration of defects in deposited layers.
+By CVD, both, the 3C \cite{kong88,powell90,powell91} as well as the 6H \cite{kong88_2,powell90_2} polytype could be successfully grown.
+In order to obtain the homoepitactically grown 6H polytype, off-axis 6H-SiC wafers are required as a substrate \cite{kimoto93}.
+%In the so called step-controlled epitaxy, lateral growth proceeds from atomic steps without the necessity of preceding nucleation events.
+Investigations indicate that in so-called step-controlled epitaxy, crystal growth proceeds through the adsorbtion of Si species at atomic steps and their carbonization by hydrocarbon molecules.
+A model is suggested ...
+
+... diffusion of reactants in a stagnant layer.
 
 
-off-axis \cite{shibahara86,powell87_2} ...
-resulting in carb and growth \cite{kitabatake97} ...
-
-lower temps ... to limit thermal stress due to differing expansion coefficients ...
-
 \section{Ion beam synthesis of cubic silicon carbide}
 
 \section{Substoichiometric concentrations of carbon in crystalline silicon}