From: hackbard Date: Fri, 22 Apr 2011 12:58:00 +0000 (+0200) Subject: finished ted X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e810f9db2bc69a3c58053a5270e3e9298492f653;p=lectures%2Flatex.git finished ted --- diff --git a/bibdb/bibdb.bib b/bibdb/bibdb.bib index fdea406..810cb9b 100644 --- a/bibdb/bibdb.bib +++ b/bibdb/bibdb.bib @@ -2347,6 +2347,69 @@ notes = "solubility of c in c-si, si-c phase diagram", } +@Article{hofker74, + author = "W. Hofker and H. Werner and D. Oosthoek and N. + Koeman", + affiliation = "N. V. Philips' Gloeilampenfabrieken Philips Research + Laboratories Eindhoven Netherlands Eindhoven + Netherlands", + title = "Boron implantations in silicon: {A} comparison of + charge carrier and boron concentration profiles", + journal = "Applied Physics A: Materials Science & + Processing", + publisher = "Springer Berlin / Heidelberg", + ISSN = "0947-8396", + keyword = "Physics and Astronomy", + pages = "125--133", + volume = "4", + issue = "2", + URL = "http://dx.doi.org/10.1007/BF00884267", + note = "10.1007/BF00884267", + year = "1974", + notes = "first time ted (only for boron?)", +} + +@Article{michel87, + author = "A. E. Michel and W. Rausch and P. A. Ronsheim and R. + H. Kastl", + collaboration = "", + title = "Rapid annealing and the anomalous diffusion of ion + implanted boron into silicon", + publisher = "AIP", + year = "1987", + journal = "Applied Physics Letters", + volume = "50", + number = "7", + pages = "416--418", + keywords = "SILICON; ION IMPLANTATION; ANNEALING; DIFFUSION; + BORON; ATOM TRANSPORT; CHARGEDPARTICLE TRANSPORT; VERY + HIGH TEMPERATURE; PN JUNCTIONS; SURFACE CONDUCTIVITY", + URL = "http://link.aip.org/link/?APL/50/416/1", + doi = "10.1063/1.98160", + notes = "ted of boron in si", +} + +@Article{cowern90, + author = "N. E. B. Cowern and K. T. F. Janssen and H. F. F. + Jos", + collaboration = "", + title = "Transient diffusion of ion-implanted {B} in Si: Dose, + time, and matrix dependence of atomic and electrical + profiles", + publisher = "AIP", + year = "1990", + journal = "Journal of Applied Physics", + volume = "68", + number = "12", + pages = "6191--6198", + keywords = "BORON IONS; ION IMPLANTATION; SILICON; DIFFUSION; TIME + DEPENDENCE; ANNEALING; VERY HIGH TEMPERATURE; SIMS; + CRYSTALS; AMORPHIZATION", + URL = "http://link.aip.org/link/?JAP/68/6191/1", + doi = "10.1063/1.346910", + notes = "ted of boron in si", +} + @Article{cowern96, author = "N. E. B. Cowern and A. Cacciato and J. S. Custer and F. W. Saris and W. Vandervorst", diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex index a55b216..19ad798 100644 --- a/posic/thesis/sic.tex +++ b/posic/thesis/sic.tex @@ -286,7 +286,7 @@ A comprehensive survey on C-mediated effects in Si has been published by Skorupa \subsection{Carbon as an impurity in silicon} -Below the solid solubility, C mainly occupies substitutionally Si lattice sites in Si \cite{newman65}. +Below the solid solubility, C impurities mainly occupy substitutionally Si lattice sites in Si \cite{newman65}. Due to the much smaller covalent radius of C compared to Si every incorporated C atom leads to a decrease in the lattice constant corresponding to a lattice contraction of about one atomic volume \cite{baker68}. The induced strain is assumed to be responsible for the low solid solubility of C in Si, which was determined \cite{bean71} to be \begin{equation} @@ -294,13 +294,14 @@ c_{\text{s}}=\unit[4\times10^{24}]{cm^{-3}} \cdot\exp(\unit[-2.3]{eV/k_{\text{B}}T}) \text{ .} \text{{\color{red}k recursive!}} \end{equation} + The barrier of diffusion of substitutional C has been determined to be around \unit[3]{eV} \cite{newman61}. However, as suspected due to the substitutional position, the diffusion of C requires intrinsic point defects, i.e. Si self-interstitials and vacancies. Similar to phosphorous and boron, which exclusively use self-interstitials as a diffusion vehicle, the diffusion of C atoms is expected to obey the same mechanism. Indeed, enhanced C diffusion was observed in the presence of self-interstitial supersaturation \cite{kalejs84} indicating an appreciable diffusion component involving self-interstitials and only a negligible contribution by vacancies. Substitutional C and interstitial Si react into a C-Si complex forming a dumbbell structure oriented along a crystallographic \hkl<1 0 0> direction on a regular Si lattice site. This structure, the so called C-Si \hkl<1 0 0> dumbbell structure, was initially suspected by local vibrational mode absorption \cite{bean70} and finally verified by electron paramegnetic resonance \cite{watkins76} studies on irradiated Si substrates at low temperatures. -Measuring the annealing rate of the defect as a function of temperature reveals barriers for migration ranging from \unit[0.73]{eV} \cite{song90} to \unit[0.87]{eV} \cite{tipping87}. +Measuring the annealing rate of the defect as a function of temperature reveals barriers for migration ranging from \unit[0.73]{eV} \cite{song90} to \unit[0.87]{eV} \cite{tipping87}, which is highly mobile compared to substitutional C. % diffusion pathway? %\subsection{Agglomeration phenomena} @@ -309,11 +310,20 @@ Measuring the annealing rate of the defect as a function of temperature reveals \subsection{Suppression of transient enhanced diffusion of dopant species} +The predominant diffusion mechanism of most dopants in Si based on native self-interstitials \cite{fahey89} has a large impact on the diffusion behavior of dopants that have been implanted in Si. +The excess population of Si self-interstitials created by low-energy implantations of dopants for shallow junction formation in submicron technologies may enhance the diffusion of the respective dopant during annealing by more than one order of magnitude compared to normal diffusion. +This kind of diffusion, labeled transient enhanced diffusion (TED), which is driven by the presence of non-equilibrium concentrations of point defects, was first discovered for implantations of boron in Si \cite{hofker74} and is well understood today \cite{michel87,cowern90,stolk95,stolk97}. +The TED of B was found to be inhibited in the presence of a sufficient amount of incorporated C \cite{covern96}. +This is due to the reduction of the excess Si self-interstitials with substitutional C atoms forming the C-Si interstitial complex \cite{stolk97,zhu98}. +Therefore, incorporation of C provides a promising method for suppressing TED enabling an improved shallow junction formation in future Si devices. + \subsection{Strained silicon and silicon heterostructures} % -> skorupa 3.2: c sub vs sic prec % -> my own links: strane etc ... % -> skorupa 3.5: heterostructures + + \section{Assumed cubic silicon carbide conversion mechanisms} \label{section:assumed_prec}