From: hackbard Date: Thu, 28 Oct 2010 16:20:54 +0000 (+0200) Subject: more applications, hurry now! ... grrr X-Git-Url: https://hackdaworld.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1503d5df72cf46fe416827eb897133eb550bdbbf;p=lectures%2Flatex.git more applications, hurry now! ... grrr --- diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex index 69d6bc6..b149b8d 100644 --- a/posic/thesis/sic.tex +++ b/posic/thesis/sic.tex @@ -57,9 +57,9 @@ Thermal conductivity [W/cmK] & 5.0 & 4.9 & 4.9 & 1.5 & 1.3 & 22 \\ 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. -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{edgar92,pensl93,morkoc94,casady96,wesch96,capano97,park98}. +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 densites. -Its formidable mechanical stability, heat resistant, radiation hardness and low neutron capture radius cross section allow operation in harsh and radiation-hard environments~\cite{capano97}. +Its formidable mechanical stability, heat resistant, radiation hardness and low neutron capture cross section allow operation in harsh and radiation-hard environments~\cite{capano97}. Despite high-temperature operations the wide band gap also allows the use of SiC in optoelectronic devices. Indeed, a forgotten figure, Oleg V. Losev discovered what we know as the light emitting diode (LED) today in the mid 1920s by observing light emission from SiC crystal rectifier diodes used in radio receivers when a current was passed through them~\cite{losev27}. @@ -68,11 +68,20 @@ However, it was Losev who continued his studies providing comprehensive knowledg And indeed, the first significant blue LEDs reinvented at the start of the 1990s were based on SiC. Due to the indirect band gap and, thus, low light emitting efficiency, however, it is nowadays replaced by GaN and InGaN based diodes. However, even for GaN based diodes SiC turns out to be of great importance since it constitutes an ideal substrate material for GaN epitaxial layer growth~\cite{liu_l02}. +As such, SiC will continue to play a major role in the production of future super-bright visible emitters. Especially substrates of the 3C polytype promise good quality, single crystalline GaN films~\cite{takeuchi91,yamamoto04,ito04}. -Due to the indirect band gap applications +The focus of SiC based applications, however, is in the area of solid state electronics experiencing revolutionary performance improvements enabled by its capabilities. +These devices include ultraviolet (UV) detectors, radio frequency (RF) amplifiers, rectifiers, switching transistors and MEMS applications. +For UV dtectors the wide band gap is useful for realizing low photodiode dark currents as well as sensors that are blind to undesired near-infrared wavelenghts produced by heat and solar radiation. +These photodiodes serve as excellent sensors applicable for monitoring and control of turbine engine combustion. +The low dark currents enable the use for X-ray, heavy ion and neutron detection in nuclear reactor monitoring and enhanced scientific studies of high-energy particle collisions as well as cosmic radiation. +The high breakdown field and carrier saturation velocity coupled with the high thermal conductivity allow SiC RF transistors to handle much higher power densities and frequencies in stable operation at high temperatures. +Smaller transistor sizes and less cooling requirements lead to a reduced overall size and cost of these systems. + + Focus on ... key ... to high efficiency -name applications related to properties: diodes, rectifiers, inverters, HDTV alternative microwave tubes +name applications related to properties: diodes, rectifiers, inverters, HDTV alternative microwave tubes, sensors high saturation drift velocity high-frequency ... Mechanical stability almost like diamond ... @@ -92,6 +101,6 @@ The unique properties driving its applications in the same time harden the fabri \section{Substoichiometric concentrations of carbon in crystalline silicon} -\section{Assumed precipitation mechanism of cubic silicon carbide in silicon} +\section{Assumed precipitation mechanism of cubic silicon carbide in bulk silicon} \label{section:assumed_prec}