From: hackbard <hackbard@sage.physik.uni-augsburg.de>
Date: Thu, 11 Nov 2010 19:08:13 +0000 (+0100)
Subject: nearly finished 1.1
X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9b32c7bd37526688ebcdb2d03eead5e67d0fffd5;p=lectures%2Flatex.git

nearly finished 1.1
---

diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex
index d4dffdb..e9b44e4 100644
--- a/posic/thesis/sic.tex
+++ b/posic/thesis/sic.tex
@@ -85,9 +85,22 @@ Thus, rectifier diodes and switching transistors with higher switching frequenci
 Therefor, SiC constitutes a promising candidate to become the key technology towards an extensive development and use of regenerative energies and elctromobility.
 Beside the mentioned electrical capabilities the mechanical stability, which is almost as hard as diamond, and chemical inertness almost suggest SiC to be used in MEMS designs.
 
-isotropic properties ...
-Since in this work 3C-SiC unit cell ... two fcc lattices ...
-
+Among the different polytypes of SiC, the cubic phase shows a high electron mobility and the highest break down field as well as saturation drift velocity.
+In contrast to its hexagonal counterparts 3C-SiC exhibits isotropic mechanical and electronic properties.
+Additionally the smaller band gap is expected to be favorable concerning the interface state density in MOSFET devices fabricated on 3C-SiC.
+Thus the cubic phase is most effective for highly efficient high-performance electronic devices.
+\begin{figure}[ht]
+\begin{center}
+\includegraphics[width=7cm]{sic_unit_cell.eps}
+\end{center}
+\caption{3C-SiC unit cell. Yellow and grey spheres correpsond to Si and C atoms respectively. Covalent bonds are illustrated by blue lines.}
+\label{fig:sic:unit_cell}
+\end{figure}
+The 3C-SiC unit cell is shown in Fig.~\ref{fig:sic:unit_cell}.
+3C-SiC grows in zincblende structure, i.e. it is composed of two fcc lattices, which are displaced by one quarter of the volume diagonal as in Si.
+However, in 3C-SiC, one of the fcc lattices is occupied by Si atoms while the other one is occupied by C atoms.
+Its lattice constant of \unit[0.436]{nm} compared to \unit[0.543]{nm} from that of Si results in a lattice mismatch of almost \unit[20]{\%}, i.e. four lattice constants of Si match five SiC lattice constants.
+Thus, the Si density of SiC is only slightly lower, i.e. \unit[97]{\%}, than that of Si.
 
 \section{Fabrication of silicon carbide}