III-Nitride Based Light Emitting Diodes and Applications

396 Pages·2013·20.548 MB·English

by  Hiroshi Amano (auth.), Tae-Yeon Seong, Jung Han, Hiroshi Amano, Hadis Morkoc (eds.)

Topics in Applied Physics
Volume126
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Tae-Yeon Seong (cid:2) Jung Han (cid:2) Hiroshi Amano (cid:2)
Hadis Morkoç
Editors
III-Nitride Based
Light Emitting
Diodes and
Applications
Editors
Tae-YeonSeong HiroshiAmano
DepartmentofMaterialsScience DepartmentofElectricalEngineering
andEngineering andComputerScience
KoreaUniversity NagoyaUniversity
Seoul,RepublicofKorea Nagoya,Aichi,Japan
JungHan HadisMorkoç
DepartmentofElectricalEngineering DepartmentofElectricalandComputer
YaleUniversity EngineeringandPhysics
NewHaven,CT,USA VirginiaCommonwealthUniversity
Richmond,VA,USA
ISSN0303-4216 ISSN1437-0859(electronic)
TopicsinAppliedPhysics
ISBN978-94-007-5862-9 ISBN978-94-007-5863-6(eBook)
DOI10.1007/978-94-007-5863-6
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Preface
Overthelasttwodecades,significantprogresshasbeenmadeinthegrowth,doping
and processing technologies of III-nitride based semiconductors which paved the
wayforhighbrightnesslightemittingdiodes(LEDs).LEDshavealreadypenetrated
trafficsignals,signagelighting,andautomotiveapplications.However,itsultimate
goal is to replace traditional lamps, such as incandescent and fluorescent varieties
fuelledbythefactthatLEDlightingsubstantiallyreducesenergyconsumptionand
thusthecarbonfootprint.DespitebreathtakingadvancesinLEDtechnologies(e.g.,
growth, doping and processing technologies), there remain critical issues for fur-
ther improvement for the realization of LED lighting. Considering that there are
alreadyseveralbooksdealingwithknownandbasicissuesinIII-nitride-basedop-
toelectronicdevicesincludingLEDsandlaserdiodes,thisbookaimstoprovidethe
readerswithcontemporaryLEDissueswhichhavenotbeencomprehensivelydis-
cussedandonwhichtheperformanceofLEDsiscriticallydependent.Forexample,
mostimportantly,theremustbeabreakthroughinthegrowthofhigh-qualitynitride
semiconductorepitaxiallayerswithlowdislocationdensity,inparticular,forAl-rich
and In-rich varieties. The materials quality is directly dependent on the substrates
used, such as sapphire, Si, etc. In addition, the loss in efficiency at high injection
levels, growth on different orientations (giving rise to polar, semi-polar and non-
polarmaterial),andpolarizationarealsoimportant.Chipprocessingandpackaging
technologiesarekeyissuesaswell.
Chapter1chroniclesthelow-temperature-depositedbufferlayersandtheimpact
theyhadonnitrideresearchandthesubsequentdevelopmentofdevices.Chapter2
deals with a perspective on the future of LED efficiency. Chapter3 reviews the
development of GaN epitaxial growth on Si using different methods and nitride
LEDperformanceonSi.Chapter4presentsthepropertiesandthefabricationpro-
cesses associated with patterned sapphire substrate (PSS) and applications of this
technologytogrowthofnon-polarandsemi-polarGaNlayers.Chapter5provides
an overview of epitaxial growth and optical properties of IIInitride LEDs on non-
and semi-polar orientations. Chapter6 presents different techniques utilized to as-
sesstheinternalquantumefficiency(IQE)inLEDs.Chapter7reviewstheIQEloss
mechanisms.Chapter8describeselectricalproperties,reliability,andelectro-static
v
vi Preface
discharge robustness of InGaN-based LEDs. Chapter9 treats simulations of light
extraction efficiency (LEE) as a function of the major materials parameters and
geometries in the mainstream LED structures. Chapter10 deals with fabrication
methodologies for high efficiency LEDs for relatively high LEE. Chapter11 pro-
videsanoverviewofphosphorsandLEDpackagingconfigurationsforwhilelight
emission. Chapter12 discusses the optoelectrical characteristics, various designs,
and developments of high voltage and alternating current (AC) LEDs. Chapter13
givesanoverviewofthefundamentalsofchromaticityandcolorrendering,thetwo
importantaspectsofcolorqualityforgenerallighting.Chapter14describespossi-
blefuturesystemlevelapplicationsofLEDsfromtheviewpointofemergingtrends
inlightingrelatedtohumanhealth,communication,anddisplaytechnologies.
Seoul,Korea Tae-YeonSeong
NewHaven,USA JungHan
Nagoya,Japan HiroshiAmano
Richmond,USA HadisMorkoç
Contents
1 Introduction Part A. Progress and Prospect of Growth
ofWide-Band-GapIII-Nitrides . . . . . . . . . . . . . . . . . . . . . 1
HiroshiAmano
1.1 HistoryofIII–VResearch(1950sto1970s) . . . . . . . . . . . . . 1
1.2 DawnofGaNResearch(1970stoMid1980s) . . . . . . . . . . . 3
1.3 Low-Temperature-DepositedBuffer Layer, p-TypeGaNand
HighlyLuminescentInGaN(Late1980s) . . . . . . . . . . . . . . 4
1.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2 IntroductionPartB.Ultra-efficientSolid-StateLighting:Likely
Characteristics,EconomicBenefits,TechnologicalApproaches . . . 11
JeffY.Tsao, JonathanJ.WiererJr., LaurenE.S.Rohwer,
MichaelE.Coltrin, MaryH.Crawford, JerryA.Simmons,
Po-ChiehHung, HarrySaunders, DmitryS.Sizov, RajBhat, and
Chung-EnZah
2.1 SomeLikelyCharacteristicsofUltra(>70%)EfficientSSL . . . . 12
2.2 TheUltimateSSLSourceIsSpiky . . . . . . . . . . . . . . . . . 14
2.2.1 SpikySpectraGiveGoodCRI . . . . . . . . . . . . . . . . 14
2.2.2 SpikySpectraGivetheHighestMWLERs . . . . . . . . . 15
2.3 EconomicBenefitsofUltra-efficientSSL . . . . . . . . . . . . . . 17
2.3.1 Scenario1:LightIsNotaFactorofProduction . . . . . . . 17
2.3.2 Scenario2:LightIsaFactorofProduction . . . . . . . . . 18
2.3.3 A Qualified Nod to Scenario 2:
MoreLight=MoreProductivity . . . . . . . . . . . . . . 19
2.4 TwoCompetingApproaches:LowandHighPowerDensities . . . 20
2.4.1 LowPowerDensityApproach(LEDs) . . . . . . . . . . . 21
2.4.2 HighPower-DensityApproach . . . . . . . . . . . . . . . 23
2.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
vii
viii Contents
3 EpitaxyPartA.LEDsBasedonHeteroepitaxialGaNonSiSubstrates 27
TakashiEgawaandOsamuOda
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2 EpitaxialGrowthandCharacterization . . . . . . . . . . . . . . . 30
3.2.1 GaNGrowthonSapphire . . . . . . . . . . . . . . . . . . 30
3.2.2 GaNGrowthonSiC . . . . . . . . . . . . . . . . . . . . . 36
3.2.3 GaN/SiUsingLowTemperature(LT)IntermediateLayers . 36
3.2.4 GaN/Si Using High Temperature (HT)
AlN/AlGaNIntermediateLayers . . . . . . . . . . . . . . 37
3.2.5 GaN/Si Using HT Intermediate Layers (ILs) and
Multilayers(MLs) . . . . . . . . . . . . . . . . . . . . . . 38
3.2.6 GaN/SiUsingSLSInterlayers . . . . . . . . . . . . . . . . 39
3.3 FabricationofLEDsandTheirPerformances . . . . . . . . . . . . 43
3.3.1 Device Characteristics of LED Structures
withHTAlN/AlGaNIntermediateLayers[62–66] . . . . . 43
3.3.2 Effect of Thin AlN Intermediate Layers
andAlN/GaNMLs[35,71–78] . . . . . . . . . . . . . . . 44
3.3.3 WaferBondingandLift-Off[79] . . . . . . . . . . . . . . 47
3.3.4 EffectoftheInsertionofSLSLayers[97–99] . . . . . . . 50
3.3.5 OtherStructures . . . . . . . . . . . . . . . . . . . . . . . 51
3.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4 EpitaxyPartB.EpitaxialGrowthofGaNonPatternedSapphire
Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
KazuyukiTadatomo
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.2 PropertiesandFabricationofPSSs . . . . . . . . . . . . . . . . . 60
4.3 GrowthofGaNonPSS,andPropertiesofGaN-LEDsonPSS . . . 62
4.3.1 SAGandELO . . . . . . . . . . . . . . . . . . . . . . . . 62
4.3.2 GaNGrowthonPSSandtheMechanismofDecreasing
DislocationDensitybyELO. . . . . . . . . . . . . . . . . 65
4.3.3 CharacteristicsofLEDsGrownonPSS . . . . . . . . . . . 67
4.4 The Principle of Light Extraction Efficiency Improvement
ofGaN-BasedLEDsbyPatternedSapphireSubstrate . . . . . . . 68
4.4.1 Impact of Surface Structure of LEDs on Light
ExtractionEfficiencyImprovement . . . . . . . . . . . . . 68
4.4.2 ThePrincipleofLightExtractionEfficiencyImprovement
ofGaN-BasedLEDsbyPatternedSapphireSubstrate . . . 69
4.4.3 DevelopmentofPSSwithMicrometer-SizedStructures . . 70
4.4.4 DevelopmentofPSSwithSub-micrometer-SizedStructures 72
4.5 NovelApplicationofPSStoGrowthofNonpolarorSemipolarGaN 75
4.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Contents ix
5 GrowthandOpticalPropertiesofGaN-BasedNon-andSemipolar
LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
MichaelKneissl,JensRass,LukasSchade,andUlrichT.Schwarz
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.2 PiezoelectricandSpontaneousPolarizationinGroup-IIINitrides . 84
5.3 GrowthofGaNandInGaNonDifferentNon-andSemipolar
SurfaceOrientations . . . . . . . . . . . . . . . . . . . . . . . . . 88
5.3.1 HeteroepitaxialGrowth of Non- and Semipolar GaN
onSapphire,Silicon,Spinel,andLiAlO Substrates . . . . 89
2
5.3.2 Surface Morphologies and Strutural Defects of Non-
andSemipolarGaNFilms . . . . . . . . . . . . . . . . . . 91
5.3.3 IndiumIncorporationinInGaNLayersandQuantum
WellsonDifferentSemipolarandNonpolarSurfaces. . . . 94
5.4 Polarization of the Light Emission from Non- and
SemipolarInGaNQWs . . . . . . . . . . . . . . . . . . . . . . . 95
5.4.1 LightEmissionfromNonpolarInGaNQWs . . . . . . . . 98
5.4.2 LightEmissionfromSemipolarInGaNQWs . . . . . . . . 99
5.5 PerformanceCharacteristicsofNon-andSemipolarInGaNQW
LightEmittingDiodes . . . . . . . . . . . . . . . . . . . . . . . . 105
5.5.1 WavelengthShift. . . . . . . . . . . . . . . . . . . . . . . 105
5.5.2 Droop . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
5.5.3 PolarizationandLightExtraction . . . . . . . . . . . . . . 108
5.5.4 3D-SemipolarLEDsonc-PlaneSapphire . . . . . . . . . . 109
5.5.5 State-of-the-Artof Non- andSemipolarBlue,Green,
andWhiteLEDs . . . . . . . . . . . . . . . . . . . . . . . 109
5.5.6 TowardsYellowLEDsandBeyond . . . . . . . . . . . . . 111
5.6 SummaryandOutlook . . . . . . . . . . . . . . . . . . . . . . . . 112
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
6 ActiveRegionPartA.InternalQuantumEfficiencyinLEDs . . . . . 121
ElisonMatioliandClaudeWeisbuch
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
6.2 AssessmentofIQEfromPhotoluminescenceMeasurements . . . . 123
6.3 Principle of IQE Assessment from Electroluminescence
Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
6.3.1 CalculationofLightExtractionEfficiencyinaSimple
GaN-BasedLED . . . . . . . . . . . . . . . . . . . . . . . 128
6.3.2 ApplicationtoLEDsGrownonBulkGaNSubstrates,
ComplexLEDStructuresandLasers . . . . . . . . . . . . 130
6.4 ExperimentalAssessmentofIQE . . . . . . . . . . . . . . . . . . 131
6.4.1 IQEMeasurementofaState-of-the-ArtLED . . . . . . . . 132
6.4.2 EL-BasedIQEMeasurementofaPoorPerformingLED:
EffectofSurfaceRoughness. . . . . . . . . . . . . . . . . 134
6.5 ModelforPhotonRecycling . . . . . . . . . . . . . . . . . . . . . 136
6.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137