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Semiconductor Glossary book, click here to see new prices!
With over 2000 terms defined and explained, Semiconductor Glossary is the most complete reference in the field of semiconductors on the market today.
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Including some 500 new terms defined and remaining terms updated and modified, a 2nd edition book version of this glossary is now available.
superlattice
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semiconductor structure comprising of several ultra-thin layers (atomic layers) engineered to obtain specific electronic and photonic properties; slight modifications of chemical composition of each layer result in slight variations of energy bandgap from layer to layer: bandgap engineering; fabrication of superlattices requires high-precision heteroepitaxial deposition methods such as MBE and MOCVD; typically involves III-V semiconductors.
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Term (Index)
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Definition
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direct bandgap semiconductor
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semiconductor in which the bottom of the conduction band and the top of the valence band occur at the momentum k=0;in the case of d.b.s. energy released during band-to-band electron recombination with a hole is converted primarily into radiation (radiant recombination); wavelength of emitted radiation is determined by the energy gap of semiconductor; examples of d.b.s. GaAs, InP, etc.
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indirect bandgap semiconductor
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semiconductor in which bottom of the conduction band does not occur at effective momentum k=0, i.e. is shifted with respect to the top of the valence band which occurs at k=0; energy released during electron recombination with a hole is converted primarily into phonon; e.g. Si, Ge, GaP.
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Term (Index)
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Definition
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energy gap, forbidden band, bandgap, Eg
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energy band separating conduction and valence bands in the solid; no electron energy levels are allowed in the forbidden band; no energy gap in metals in which case conduction and valence bands overlap; solids featuring energy gap are defined as either semiconductors or insulators based on the width of energy gap; values of Eg (at 300K) for common semiconductors:
InSb - 0.17 eV, Ge - 0.67 eV, Si - 1.12 eV, GaAs - 1.43 eV GaP - 2.26 eV, 6H-SiC - 2.9 eV, GaN - 3.5 eV,
and insulators Ta2O5 - 4.2 eV , TiO2 -5 eV, Si3N4 - 5.1, Al2O3 ~5 eV, SiO2 - 8.0
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conduction band
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the upper energy band in semiconductor separated by the energy gap (bandgap)from the valance band; c.b. is not completely filled with electrons, hence, electrons can conduct in the conduction band.
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valence band
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energy band in semiconductor that is filled with electrons at 0 K; electrons cannot conduct in valence band.
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Term (Index)
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Definition
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indirect bandgap semiconductor
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semiconductor in which bottom of the conduction band does not occur at effective momentum k=0, i.e. is shifted with respect to the top of the valence band which occurs at k=0; energy released during electron recombination with a hole is converted primarily into phonon; e.g. Si, Ge, GaP.
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direct bandgap semiconductor
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semiconductor in which the bottom of the conduction band and the top of the valence band occur at the momentum k=0;in the case of d.b.s. energy released during band-to-band electron recombination with a hole is converted primarily into radiation (radiant recombination); wavelength of emitted radiation is determined by the energy gap of semiconductor; examples of d.b.s. GaAs, InP, etc.
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Term (Index)
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Definition
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wide bandgap semiconductor
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semiconductor featuring energy gap Eg > 2.5 eV (rather arbitrary criterion), useful in high temperature applications and emission of blue radiation (should feature direct bandgap at the same time); e.g. SiC (Eg = 2.9 eV), GaN (Eg = 3.5 eV), ZnS (Eg = 3.68 eV)
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gallium nitride, GaN
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wide bandgap III-V semiconductor featuring direct bandgap 3.5 eV wide; among very few semiconductors capable of generating blue radiation; number one candidate for blue LEDs and lasers;
see "GaN note" on www.semiconductornotes.com for more information.
Reference: See Semiconductor Notes for more information on GaN
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silicon carbide, SiC
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semiconductor featuring energy gap Eg = 2.9 -3.05 eV (wide bandgap semiconductor), indirect bandgap; SiC can be obtained in several polytypes- most common hexagonal in the form of either 4H or 6H polytypes; parameters vary depending on polytype; higher than Si and GaAs electron saturation velocity; carrier mobility: electrons 100-500 cm2/Vs, holes 20 cm2/Vs; thermal conductivity 3 W/cmK (two times higher than Si); excellent semiconductor, however, difficult and expensive to fabricate in the form of single-crystal wafers; best suited for high power, high temperature devices; also limited use in photonic devices (e.g. substrate for GaN).
Reference: SemiOneSource,Notes
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Zinc sulfide, ZnS
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II-VI semiconductor, has a largest bandgap among semiconductors considered for practical applications (Eg = 3.68 eV) which in conjunctions with a bandgap being direct makes ZnS potentially attractive as a blue light emitter.
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diamond
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single-crystal carbon; material featuring outstanding semiconductor properties; wide bandgap semiconductor; in theory the best semiconductor, in practice very difficult to form in shapes and quantities compatible with manufacturing of semiconductor devices; also, restrictions on p-n junction formation due to the lack of adequate dopants.
Reference: More information on semiconductor materials
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Jerzy Ruzyllo is a Distinguished Professor Emeritus in the Department of Electrical Engineering at Penn State University.
This book gives a complete account of semiconductor engineering covering semiconductor properties, semiconductor materials, semiconductor devices and their uses, process technology, fabrication processes, and semiconductor materials and process characterization.
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