From: hackbard Date: Thu, 22 Oct 2009 17:29:52 +0000 (+0200) Subject: more or less finished intro (only chapter declarations left) + started si/c facts X-Git-Url: https://hackdaworld.org/gitweb/?p=lectures%2Flatex.git;a=commitdiff_plain;h=ad40889b5a4dd7247e0c609a8e0d02fa74250fd9 more or less finished intro (only chapter declarations left) + started si/c facts --- diff --git a/posic/thesis/intro.tex b/posic/thesis/intro.tex index dc1e041..bb0f9ad 100644 --- a/posic/thesis/intro.tex +++ b/posic/thesis/intro.tex @@ -19,16 +19,14 @@ These C-Si dumbbells agglomerate and once a critical radius is reached, the topo A better understanding of the supposed SiC conversion mechanism and related carbon-mediated effects in silicon will enable significant technological progress in SiC thin film formation on the one hand and likewise offer perspectives for processes which rely upon prevention of precipitation events for improved silicon based devices on the other hand. Implanted carbon is known to suppress transient enhanced diffusion (TED) of dopant species like boron or phosphorus in the annealing step \cite{cowern96} which can be exploited to create shallow p-n junctions in submicron technologies. Si self-interstitials (Si$_{\text{i}}$), known as the transport vehicles for dopants \cite{fahey89,stolk95}, get trapped by reacting with the carbon atoms. -Furthermore, carbon incorporated in silicon is being used to adjust the band gap \cite{soref91,kasper91} and the fabrication of strained silicon \cite{strane94,strane96,osten99} in order to obtain higher charge carrier mobilities \cite{chang05,osten97}. - -Thus, the understanding of carbon in silicon either as isovalent impurity as well as at concentrations exceeding the solid solubility limit up to the stoichiometric ratio to form silicon carbide is of fundamental interest. -Atomistic simulations offer -In particular the last step of the SiC conversion, which cannot - -Computer simulations ... -\\ +Furthermore, carbon incorporated in silicon is being used to fabricate strained silicon \cite{strane94,strane96,osten99} utilized in semiconductor industry for increased charge carrier mobilities in silicon \cite{chang05,osten97} as well as to adjust its band gap \cite{soref91,kasper91}. +Thus the understanding of carbon in silicon either as an isovalent impurity as well as at concentrations exceeding the solid solubility limit up to the stoichiometric ratio to form silicon carbide is of fundamental interest. +Due to the impressive growth in computer power on the one hand and outstanding progress in the development of new theoretical concepts, algorithms and computational methods on the other hand, computer simulations enable the modelling of increasingly complex systems. +Atomistic simulations offer a powerfull tool to study materials and molecular systems on a microscopic level providing detailed insight not accessible by experiment. +The intention of this work is to contribute to the understanding of C in Si by means of atomistic simulations targeted on the task to elucidate the SiC conversion mechanism in silicon. +The outline of this work is as follows: In chapter ... diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex new file mode 100644 index 0000000..8d7ac2c --- /dev/null +++ b/posic/thesis/sic.tex @@ -0,0 +1,27 @@ +\chapter{Review of the silicon carbon compound} + +\section{Properties and applications of silicon carbide} + +The stoichiometric composition of silicon and carbon termed silicon carbide (SiC) is the only chemical stable compound in the C/Si system \cite{}. +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}. +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. + +\subsection{SiC polytypes} + +Each of the four sp$^3$ hybridized orbitals of the 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 covalent $\sigma$ bond of equal length and strength for each atom with its neighbours. + +Although the local order of Si and C next neighbour 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, closed-packed SiC bilayers. + +\section{Fabrication of silicon carbide} + +\section{Ion beam synthesis of cubic silicon carbide} + +\section{Assumed precipitation mechanism of cubic silicon carbide in silicon} + +\section{Substoichiometric concentrations of carbon in crystalline silicon} +