Understanding Modern Transistors and Diodes

355 Pages·2010·2.866 MB·English

by  Pulfrey D.L.

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UnderstandingModernTransistorsandDiodes
Writteninaconcise,easy-to-readstyle,thistextforseniorundergraduateandgraduate
coursescoversallkeytopicsthoroughly.Itisalsoausefulself-studyguideforpractising
engineerswhoneedacomplete,up-to-datereviewofthesubject.
Keyfeatures:
(cid:1)
Rigoroustheoreticaltreatmentcombinedwithpracticaldetail
(cid:1)
AtheoreticalframeworkbuiltupsystematicallyfromtheSchro¨dingerWaveEquation
andtheBoltzmannTransportEquation
(cid:1)
CoversMOSFETS,HBTs,HJFETS,solarcellsandLEDs.
(cid:1)
UsesthePSPmodelforMOSFETS
(cid:1)
Describestheoperationofmodern,high-performancetransistorsanddiodes
(cid:1)
Evaluates the suitability of various transistor types and diodes for specific modern
applications
(cid:1)
Examines solar cells and LEDs for their potential impact on energy generation and
reduction
(cid:1)
Includes a chapter on nanotransistors to prepare students and professionals for the
future
(cid:1)
Rigoroustreatmentofdevicecapacitance
(cid:1)
Providesresultsofdetailednumericalsimulationstocomparewithanalyticalsolutions
(cid:1)
End-of-chapterexercisestoaidunderstanding
(cid:1)
Onlineavailabilityofsetsoflectureslidesforundergraduateandgraduatecourses
DavidL.PulfreyisaProfessorintheDepartmentofElectricalandComputerEngineering
at the University of British Columbia, Canada, where he has been since receiving his
Ph.D.in1968fromtheUniversityofManchester,UK.Hehaswonteachingawardsat
theuniversity-,provincial-andinternational-levels.Mostrecentlyhewonthe2009IEEE
ElectronDevicesSocietyEducationAward“forcontributionstotheteachingofelectron
devicesatboththeundergraduateandgraduatelevels”.Hehasreceivedrecognitionfor
hisresearchworkonawiderangeofsemiconductordevicesbybeingelectedFellowof
theIEEEin2000,andFellowoftheCanadianAcademyofEngineeringin2003.
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Understanding Modern
Transistors and Diodes
DAVID L. PULFREY
DepartmentofElectricalandComputerEngineering
UniversityofBritishColumbia
Vancouver,BCV6T1Z4
Canada
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CAMBRIDGE UNIVERSITY PRESS
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Cambridge University Press
The Edinburgh Building, Cambridge CB2 8RU, UK
Published in the United States of America by Cambridge University Press, New York
www.cambridge.org
Information on this title: www.cambridge.org/9780521514606
© Cambridge University Press 2010
This publication is in copyright. Subject to statutory exception and to the
provision of relevant collective licensing agreements, no reproduction of any part
may take place without the written permission of Cambridge University Press.
First published in print format 2010

ISBN-13 978-0-521-51460-6 Hardback
Cambridge University Press has no responsibility for the persistence or accuracy
of urls for external or third-party internet websites referred to in this publication,
and does not guarantee that any content on such websites is, or will remain,
accurate or appropriate.
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ToEileen
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Contents
Preface pagexv
1 Introduction 1
2 Energybandbasics 3
2.1 Periodicstructures 3
2.2 Periodicpotential 4
2.3 Schro¨dinger’sequation 6
2.4 Energybands 7
2.5 Reduced-zoneplot 10
2.6 Originofthebandgaps 11
2.7 Quantumstatesandmaterialclassification 12
2.8 Bandstructureofrealsemiconductors 13
2.9 Crystalmomentumandeffectivemass 16
2.9.1 Negativeeffectivemass 18
2.9.2 Holepolarity 20
2.9.3 Parabolic-bandapproximation 20
2.10 Constant-energysurfaces 21
2.11 Effective-massSchro¨dingerequation 23
2.11.1 Boundaryconditionsfortheeffective-mass
equation 25
2.12 Energy-banddiagram 25
2.13 Frommicroscopictomacroscopic 26
Exercises 26
References 28
3 Electronandholeconcentrations 30
3.1 Creationofelectronsandholes 30
3.1.1 Thermalgeneration 30
3.1.2 Opticalgeneration 33
3.1.3 Electricalgeneration 34
3.1.4 Chemicalgeneration 35
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viii Contents
3.2 Recombination 37
3.2.1 Band-to-bandrecombination 38
3.2.2 Recombination-generation-centrerecombination 39
3.2.3 Augerrecombination 40
3.2.4 Recombinationlifetime 41
3.3 Carrierconcentrations 43
3.4 Density-of-stateseffectivemassesinsilicon 46
3.4.1 Electrons 46
3.4.2 Holes 46
Exercises 47
References 48
4 Thermalequilibrium 49
4.1 Collisions 49
4.2 TheFermilevel 51
4.3 EquilibriumcarrierconcentrationsandtheFermilevel 53
4.4 Equationsinvolvingintrinsicproperties 56
4.5 Meanunidirectionalvelocityofanequilibriumdistribution 57
4.5.1 Effectivemassandv 60
R
4.5.2 Currentandv 60
R
Exercises 61
References 62
5 Chargetransport 63
5.1 Charge,currentandenergy 63
5.2 TheBoltzmannTransportEquation 64
5.2.1 TheMethodofMoments 65
5.2.2 Thecontinuityequations 65
5.3 Thedeviceequationset 69
5.4 Mobility 71
5.4.1 Empiricalexpressionsformobility 73
5.4.2 Conductivityeffectivemass 74
5.5 Current 75
5.5.1 Driftcurrent 76
5.5.2 Diffusioncurrent 77
5.5.3 Thermalcurrent 79
5.6 Ballistictransport 80
5.7 Tunnelling 81
5.7.1 Probabilitydensitycurrent 81
5.7.2 Transmissionprobability 83
5.7.3 Tunnelcurrent 85
Exercises 87
References 90