Epitaxial growth and properties of KT[a]O[3] and related alloys

2005·6 MB·English

by  Bae, Hyung-Jin

EPITAXIALGROWTHANDPROPERTIESOFKTa0 ANDRELATEDALLOYS
3
By
HYUNG-JINBAE
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL
OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT
OFTHEREQUIREMENTSFORTHEDEGREEOF
DOCTOROFPHILOSOPHY
UNIVERSITYOFFLORIDA
2005
Tomyfamilyfortheirloveandpassion.
ACKNOWLEDGMENTS
Ithankmyparentsforencouragingandsupportingmetokeeppursuingmygoals.
Withoutthem,IwouldnotbeinthispositionwithmyPhDdegree.Also,Ithankmy
sister,whohelpedmebylivingwithmefortwoyearswhileIwasstudyingforqualifying
exam.Shemademeconcentrateonmystudy.Also,Ithankmyonlybrother-in-law,Dan
fortakingcareofmysisterandtheirson,myfirstnephew,Danny.
Also,Ithankmyhostfatherandmother,JanandMikeMartin,whowasvice
presidentintheCollegeofAgriculturalandLifeSciences,andiscurrentlyworkingas
PresidentatNewMexicoStateUniversity.TheyhelpedmetosettledowninGainesville
withoutfeelinghomesickmyfirstyearatUF,gavemegreatadviceformyacademic
career.Inaddition,myhostmomhelpedmysisterplanandorganizeherwedding,and
caredforherasalovingmother.Icurrentlykeepintouchwiththem,andIconsiderthem
mysecondfamily.
Ihavebeenhonoredtoworkwithamarvelousadvisorandgroupmembersherein
theMaterialsScienceandEngineeringDepartmentattheUniversityofFlorida.
IthankDr.Norton,whohasguidedmetoreachthispositionwithhisadviceand
support.AndIwouldliketogivemyappreciationtomycommitteemembers:Dr.
CammyR.Abernathy,Dr.StephenJ.Pearton,,Dr.SusanSinnott,andDr.Toshikazu
Nishida.
Finally,Iwouldliketothankallofmyformerandpresentgroupmembers:Dr.
JenniferSigman,Dr.Young-wooHeo,Dr.She-jinPark,DrYong-wookKwon,George,
Matt,Hyun-sik,Charlee,Seemant,Ryan,Patrick,LiChia,Yuanjie,andDaniel,who
encouragedme.
IV
8
TABLEOFCONTENTS
page
ACKNOWLEDGMENTS
....iii
LISTOFTABLES ..viii
LISTOFFIGURES ix
ABSTRACT ...xiv
CHAPTER
INTRODUCTION
1 1
2LITERATUREREVIEW 5
2.1PerovskiteMaterials 5
2.1.1OriginandStructureofPerovskites 5
2.1.2VariousPropertiesofPerovskites 5
2.1.3Applications 8
2.2PropertiesofKTa03,KNb03,andK(Ta,Nb)03 8
2.3DielectricProperties 10
2.3.1CapacitanceandPolarization 10
2.3.2DielectricLoss 12
2.3.3DielectricBreakdown 13
2.3.3.1IntrinsicBreakdown 13
2.3.3.2ThermalBreakdown 14
2.4InterdigitalElectrodeforCapacitanceMeasurements 14
2.5O2v.e6.r4viewofTunableMicrowave 16
2.6PulsedLaserDeposition(PLD) 17
2.6.1Overview 17
2.6.2PLDsystemconfiguration 1
2.6.2.1Laser(LightAmplificationbyStimulatedEmissionofRadiation).18
2.6.2.2Optics 21
2.6.2.3DepositionSystem 22
2.6.3LaserandTargetInteraction(Phenomenainsidedepositionchamber) 22
2.6.4OriginofSplashing 24
BackgroundGasEffect 26
2.7DefectChemistry 26
2.8Characterization 29
2.8.1X-RayDiffraction(XRD) 29
2.8.2FourCircleXRD 30
2.8.3AtomicForceMicroscopy(AFM) 30
2.8.4TransmissionElectronMicroscopy(TEM) 31
2.8.5Flailmeasurement 32
2.8.6CapacitanceandVoltageMeasurements 33
3SURFACETREATMENTFORFORMINGUNIT-CELLSTEPSONTHE(001)
KTa03SUBSTRATESURFACE 48
3.1Introduction 48
3.2ExperimentalMethods 49
3.3ResultsandDiscussion 50
3.4Conclusion 53
4GROWTHOFSEMICONDUCTINGKTa03THINFILMS 64
4.1Introduction 64
4.2ExperimentalMethods 65
8 4.3ResultsandDiscussion 66
4.4Conclusion 68
5DIELECTRICPROPERTIESOFTi-DOPEDK(Ta,Nb)03THINFILMSGROWN
BYPULSEDLASERDEPOSITION 73
5.1Introduction 73
5.2ExperimentalMethods 75
5.3ResultsandDiscussion 76
5.4Conclusion 81
6LOFWILDMISEGLERCOTWRINCBLYOSPSUELSSEINDALNANSEERALDEEDPOTSiI-TDIOOPNEDK(Ta,Nb)03THIN 95
6.1Introduction 95
6.2ExperimentalMethods 95
6.3ResultsandDiscussion 96
6.4Conclusion 99
7THBIYCKPNLEDSSDEPENDENTTUNABILITYFORTi-DOPEDK(Ta,Nb)03FILM 110
7.1Introduction 110
7.2ExperimentalMethods 111
7.3ResultsandDiscussion 112
7.4Summary 116
SUMMARY 129
LISTOFREFERENCES 131
BIOGRAPHICALSKETCH 143
Vll
1-
2-
LISTOFTABLES
Table Page
1.Substratesforferroelectricoxide 4
1.ApplicationsofPerovskitesinMaterials 8
2-2.Excimerlaseroperatingwavelength 20
2-3.Transmittancerangeforvariouslensandwindowmaterials 22
viii
LISTOFFIGURES
Figure page
2-1.Perovskitestructure 34
2-2.Ferroelectrichysteresisloop 34
2-3.DielectricconstantsasafunctionoftemperatureforKNb03 35
2-4.Applicationfieldsandfundamentaltechnicaltermsinfutureoxideelectronics 35
2-5.Schematicdiagramsof(a)ParallelplatecapacitorofareaAandseparationdin
vacuumattachedtoavoltagesourceand(b)parallelplatecapacitorwith
dielectricmaterialbetweentwoplates 36
2-6.Definitionofelectricdipolemoment 37
2-7.Schematicrepresentationofdifferentmechanismsofpolarization 38
2-8.Frequencydependenceofseveralcontributionstothepolarizability 39
2-9.Appliedvoltage,charging,loss,andtotalcurrentsforacapacitor 39
2-10.Schematicdiagramofseveralcapacitormeasurementtechniques 40
2-11.Schematicdiagramof(a)Interdigitalcapacitor(IDC)structureand(b)top
electrodes 41
2-12.Schematicdiagramsofphotoninteractiontoproducelaser;(a)non-lasingState,
(b)excitationofatomsusinglightsource,(c)photonemission,(d)stimulated
emissionoffurtherphotons,and(e)columnoflaserlightleavingoptical
oscillator 42
2-13.Schematicdiagramofpulsedlasersystem(PLD) 43
2-14.Varioustypeofdefectstypicallyfoundinceramics.Misplacedatomscanonly
occurincovalentceramicsduetochargeconsiderations 44
2-15.Bragg’slaw 45
2-16.Geometryoffourcirclex-ray 45
IX
2-
23--17.Schematicdiagramofatomicforcemicroscopy 46
18.SchematicdiagramofthegeometryofVanderPauwmeasurements;(a)
resistivity,and(b)Hallconstant,Rh 47
1.AFMimageofachemically-mechanicallypolishedKTa03surface 54
3-2.AFMimagesofaKTaC^surfacethatwas:(a)annealedat900°Cfor4h,and(b)
annealedat1000°Cfor4h 55
3-3.AFMimagesofaKTaC>3surfacethatwas:(a)etched18minonly,and(b)etched
15min,thenannealed700°Cfor3h 56
3-4.AFMimagesofsurface-treatedKTa03asafunctionofetchingtimewithBOE
andthenannealedat700°Cfor4h:(a)12min,(b)15min,(c)30min(5pmx5
pm),and(d)surfacesectionin(b) 57
3-5.RMSsurfaceroughnessvaluesofsurface-treatedKTaCbasafunctionofetching
timewithBOEandthenannealedat700°Cfor4h 58
3-6.AFMimagesofsurface-treatedKTa03asafunctionofetchingtimewithBOE
andthenannealedat900°Cfor4h:(a)withoutetching,(b)2min,(c)5min,
and(d)30min(1pmx1pm) 59
3-7.EnlargedAFMimageofKTa03etchedwithBOEfor2minfollowedby
annealingat900°C(1pmx1pm) 60
3-8.RMSsurfaceroughnessvaluesofsurfacetreatedKTa03asafunctionofetching
timewithBOEandthenannealedat900°Cfor4h 61
3-9.AwFiMthoiumtageetcshoinfgaaKnTda(0b)3asfitnegrleetccrhyesdtailnsBurOfEacefoarnnleOamliendat1000°Cfor1h(a) 62
3-10.AFMimagesofaKTa03single-crystalsurfacethatwas(a)etchedinBOEfor
18min,thenannealedat700°Cfor3hwithKTa03powder. TheRMS
raroeugAhFneMssiwmaasges1.o3f8a5nKmT(aR03MSsuorffapcaerttihcalte-wfarseeeatrcehaed:0i.n4B50OEnm)fo.rA8lmsionsahnodwtnhe(nb)
annealedat1000°Cfor3hwithKTa03powder. TheRMSwas4.980nm,(inthe
particle-freearea:0.580nm) 63
4-1.SchematicdiagrmamofthesegmentedKTa03/KN03target 69
4-2.X-raydiffractionresultsofKTa03:CafilmgrownonMgO(100)substrateasa
functionofdepositiontemperature 69
4-3.X-raydiffractionresultsofKTa03:CafilmgrownonMgO(100)substrateasa
functionofdifferentoxygenpressureatdepositiontemperatureof700°C 70
x