From: hackbard Date: Sun, 25 Sep 2011 21:47:39 +0000 (+0200) Subject: only commas ... faster! X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a498ec4871627a0d0dc230022a5166af1db7d702;p=lectures%2Flatex.git only commas ... faster! --- diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex index 193148b..e933b3f 100644 --- a/posic/thesis/sic.tex +++ b/posic/thesis/sic.tex @@ -14,13 +14,13 @@ In the solid state the stoichiometric composition of silicon and carbon termed s \end{figure} SiC was first discovered by Henri Moissan in 1893 when he observed brilliant sparkling crystals while examining rock samples from a meteor crater in Arizona. He mistakenly identified these crystals as diamond. -Although they might have been considered \glqq diamonds from space\grqq{} Moissan identified them as SiC in 1904~\cite{moissan04}. +Although they might have been considered \glqq diamonds from space\grqq{}, Moissan identified them as SiC in 1904~\cite{moissan04}. In mineralogy SiC is still referred to as moissanite in honor of its discoverer. It is extremely rare and almost impossible to find in nature. SiC is a mainly covalent material in which both, Si and C atoms are sp$^3$ hybridized. Each of the four sp$^3$ hybridized orbitals of a Si atom overlaps with one of the four sp$^3$ hybridized orbitals of the four surrounding C atoms and vice versa. -This results in fourfold coordinated mostly covalent $\sigma$ bonds of equal length and strength for each atom with its neighbors. +This results in fourfold coordinated, mostly covalent $\sigma$ bonds of equal length and strength for each atom with its neighbors. Although the local order of Si and C next neighbor atoms characterized by the tetrahedral bonding is the same, more than 250 different types of structures called polytypes of SiC exist~\cite{fischer90}. The polytypes differ in the one-dimensional stacking sequence of identical, close-packed SiC bilayers. Each SiC bilayer can be situated in one of three possible positions (abbreviated a, b or c) with respect to the lattice while maintaining the tetrahedral bonding scheme of the crystal. @@ -66,9 +66,9 @@ Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\ % todo add more refs + check all values! Different polytypes of SiC exhibit different properties. Some of the key properties are listed in Table~\ref{table:sic:properties} and compared to other technologically relevant semiconductor materials. -Despite the lower charge carrier mobilities for low electric fields SiC outperforms Si concerning all other properties. +Despite the lower charge carrier mobilities for low electric fields, SiC outperforms Si concerning all other properties. The wide band gap, large breakdown field and high saturation drift velocity make SiC an ideal candidate for high-temperature, high-power and high-frequency electronic devices exhibiting high efficiency~\cite{wesch96,morkoc94,casady96,capano97,pensl93,park98,edgar92}. -In addition the high thermal conductivity enables the implementation of small-sized electronic devices enduring increased power densities. +In addition, the high thermal conductivity enables the implementation of small-sized electronic devices enduring increased power densities. Its formidable mechanical stability, heat resistance, radiation hardness and low neutron capture cross section allow operation in harsh and radiation-hard environments~\cite{capano97}. In addition to high-temperature operations, the wide band gap also allows the use of SiC in optoelectronic devices.