Table Of ContentCompound
Semiconductors
Pan Stanford Series on Renewable Energy — Volume 2
Compound
Semiconductors
Physics, Technology, and Device Concepts
editors
Ferdinand Scholz
Preben Maegaard
Anna Krenz
Wolfgang Palz
The Rise of Modern Wind Energy
Wind Power
for the World
September5,2017 15:54 PSPBook-9inx6in 00-Compound-Semiconductors-Prelims
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August19,2017 11:31 PSPBook-9inx6in 00-Compound-Semiconductors-Prelims
Contents
Preface ix
1 Basics 1
1.1 WhatIsaSemiconductor? 1
1.2 NaiveBandDiagram 2
1.3 CrystalLattice:Basics 5
1.3.1 CrystalPlanes,MillerIndices 10
1.3.2 ReciprocalLattice 11
1.4 MoreDetailsaboutBandStructure 14
1.4.1 Insert:VeryShortIntroductiontoQuantum
Mechanics 15
1.4.2 Schro¨dingerEquationandDispersion
Relation 17
1.4.3 ShortSummaryUptoNow 19
1.5 EffectiveMass 19
1.6 MovementofCarriers:ConceptofHole 21
1.7 RealBandStructures 21
1.8 TemperatureDependenceofLatticeConstantand
BandGap 23
1.9 InteractionwithLight 24
1.10 CarrierStatistics 27
1.10.1 DensityofStates 28
1.10.2 FermiDistribution 31
1.11 DefectsinSemiconductors 34
2 IntroductiontoCompoundSemiconductors 39
3 BulkCrystalGrowth 47
3.1 CzochralskiMethod 49
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vi Contents
3.2 BridgmanCrystalGrowth 52
3.3 WaferPreparation 55
4 EpitaxialMethods 59
4.1 LiquidPhaseEpitaxy(LPE) 60
4.1.1 ControlofGrowthRateandLayerThickness 62
4.1.2 LPEEquipment 63
4.2 VaporPhaseEpitaxy(VPE) 66
4.3 MetalorganicVaporPhaseEpitaxy 69
4.4 MolecularBeamEpitaxy 89
4.4.1 EquipmentDetails 91
4.5 ComparisonofEpitaxialMethods 106
5 ElectricalPropertiesofSemiconductors/Electrical
Characterization 109
5.1 CarrierConcentrationandDoping 109
5.2 CarrierMobility 113
5.3 MeasurementofElectricalProperties 116
5.3.1 HallEffect 116
5.3.2 C–V Profiling 118
5.4 SecondaryIonMassSpectrometry 123
6 OpticalProcessesinSemiconductors:OpticalSpectroscopy 129
6.1 BasicOpticalProcesses 129
6.2 Steady-StateExcitation 131
6.3 OpticalCharacterizationMethods 138
6.3.1 Photoluminescence 139
6.3.2 Absorption 141
6.3.3 LateralAbsorptionandGainSpectroscopy 145
6.3.4 FourierSpectroscopy 146
6.3.5 OtherRelatedMethods 147
6.4 SomeTechnicalDetails 148
7 X-RayDiffraction 153
7.1 Basics 153
7.2 WhatCanBeMeasured? 155
7.3 DiffractometerEquipment 161
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Contents vii
8 QuantumWells 167
8.1 SemiconductorHeterojunction 167
8.2 QuantumWell:Eigenstates 168
8.3 DensityofStates 174
8.4 Behavioratk(cid:2) (cid:3)=0 175
8.5 HighCarrierMobilityinaQuantumWell 176
8.6 CouplingofSeveralQuantumWells:Resonant
Tunneling 177
9 Strain 181
9.1 ElasticDeformationofaSolid 182
9.2 InfluenceonElectronicBandStructure 185
9.3 CriticalThickness 190
9.4 UsefulnessofStrain 192
10 Low-DimensionalSystems 195
10.1 BandStructure,etc. 195
10.2 FabricationofLow-DimensionalStructures 199
10.3 PropertiesofSelf-AssembledDots 205
11 GroupIIINitrides 209
11.1 BasicProperties 210
11.2 BulkMaterial,Substrates 213
11.3 Hetero-Epitaxy,DefectReduction 217
11.4 DopingofGaN 220
11.5 TernaryAlloys 221
11.6 PolarizationandPiezoelectricity 222
11.7 DilutedNitrides 226
12 OptoelectronicDevices 229
12.1 Light-EmittingDiode 229
12.1.1 OpticalTransitions 230
12.1.2 InternalandExternalEfficiencies 232
12.1.3 LuminousEfficacy 234
12.1.4 LEDColors,WhiteLEDs 236
12.1.5 LEDEfficiencies 239
12.2 SemiconductorLaserDiodes 239
12.2.1 Gain 240
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viii Contents
12.2.2 ResonatorandFeedback 241
12.2.3 ElectricalPumping 242
12.2.4 OpticalWaveguideandConfinement 243
12.2.5 TemperatureBehavior 246
12.2.6 LateralConfinement 247
12.2.7 NearField,FarField 249
12.2.8 DistributedFeedbackLasers 249
12.2.9 Vertical-CavitySurface-EmittingLaser 252
12.3 SolarCells 256
12.3.1 BasicWorkingPrinciple 256
12.3.2 SolarSpectrum 259
12.3.3 CompoundSemiconductorsand
Photovoltaics 260
12.3.4 Multi-JunctionSolarCell 261
12.3.5 ConcentratorCells 264
12.3.6 PVSystemswithHighestEfficiency 265
13 ElectronicDevices 271
13.1 Field-EffectTransistor 271
13.2 HeterobipolarTransistor 275
References 279
Index 287
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Preface
Thisbookisbasedonalectureabout“CompoundSemiconductors,”
which I have been teaching for many years at Ulm University. It
touchesalotoftopicswhich,bythemselves,couldbeandaretaken
as subjects for other excellentin-depth textbooks.I have indicated
suchtextbookswhereverappropriatetohelptheinterestedreader
gather more detailed information. However, the main idea of this
book is to provide a good general view of this semiconductor
family without getting lost in too many details. The reader should
acquire all relevant information about this class of semiconductor
materials and the technology and processing to synthesize them
andfabricaterespectivedevicestructures.Moreover,thetheoretical
basis and the most important characterization methods for these
materials and structures will be discussed. In contrast to silicon,
mostcompoundsemiconductorshaveadirectbandstructure.That
is why they are without any doubt the backbone of the optoelec-
tronics industry. They are also perfectly suited for nanostructure
applications. Moreover, their material properties such as carrier
mobility,saturationvelocity,andbreakdownfieldsallowtheiruseas
abasisforhigh-frequencyhigh-powerelectronicdevices.According
to their technical relevance, the major focus is set to the so-called
III-Vcompoundsemiconductorscomposedofelementsofthethird
and fifth groups of the periodic system of elements. The major
representativeofthemisGaAs,whichisoftentakenastheleading
example of this module. In recent years, group III nitrides with
GaN as their most important representative have acquired ever-
increasingrelevanceinallkindsofvisibleandUVlightemission,etc.
Hence,aspecialchapterisdevotedtothesematerials.
The book begins with the presentation of the main principles
of semiconductor physics to set a basis for understanding the
