Growth and characterization of diamond _d63-doped [delta-doped] layers for FET applications [Elektronische Ressource] / von Hayssam el-Hajj

Informations

• Publié par: universitat_ulm
• Publié le: 01 janvier 2009
• Nombre de lectures: 25
• Langue: English
• Poids de l'ouvrage: 12 Mo

Extrait

GrowthandCharacterizationofDiamondδ Doped
LayersforFETApplications
Dissertation
zurErlangungdesakademischenGradeseines
Doktor Ingenieurs
(Dr. Ing.)
derFakultätfürIngenieurwissenschaften
undInformatikderUniversitätUlm
von
M.Sc. HAYSSAMEL HAJJ
AUSSAIDA
Gutachter: Prof. Dr. Ing. E.Kohn
Prof. Dr. P.Unger
AmtierenderDekan: Prof. Dr. Ing. MichaelWeber
Ulm, 31. März2009Contents
Contents i
ListofFigures v
ListofTables xi
1 Summary 1
2 Introduction 5
3 PropertiesofDiamond 9
3.1 Crystalstructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 BandStructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3 ElectricalPropertiesofDiamond . . . . . . . . . . . . . . . . . . . . . . . 11
3.4 DiamondasaSemiconductor . . . . . . . . . . . . . . . . . . . . . . . . . 11
4 ConceptsandPrinciplesofDiamondGrowth 15
4.1 HighTemperatureHighPressureGrowth(HTHP) . . . . . . . . . . . . . . 16
4.2 ChemicalVaporDeposition(CVD) . . . . . . . . . . . . . . . . . . . . . . 16
4.2.1 HotFilamentCVD(HFCVD) . . . . . . . . . . . . . . . . . . . . 18
4.2.2 MicrowavePlasmaCVD(MWPCVD) . . . . . . . . . . . . . . . . 19
4.3 PrinciplesofdiamondCVDgrowth . . . . . . . . . . . . . . . . . . . . . 19
4.4 Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.4.1 SinglecrystallineCVDdiamondonHTHPstones . . . . . . . . . . 22
ICONTENTS
5 BulkDopingofDiamond 25
5.1 N TypeDoping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.1.1 Nitrogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.1.2 Phosphorous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.2 P TypeDiamond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.2.1 Hydrogenterminateddiamondsurface . . . . . . . . . . . . . . . . 30
5.2.2 BulkDopingwithBoron . . . . . . . . . . . . . . . . . . . . . . . 31
6 Diamondδ Doping 33
6.1 Electrochemicalprofilingofboron delta dopedlayers . . . . . . . . . . . . 35
6.2 Requirementsandconditions . . . . . . . . . . . . . . . . . . . . . . . . . 38
6.3 GrowthProcedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
6.4 Conclusionongrowth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
7 CharacterizationofBoronδ DopedLayersforElectronics 43
7.1 Photoluminescence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
7.2 SheetResistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
7.3 CapacitanceVoltageMeasurement . . . . . . . . . . . . . . . . . . . . . . 45
7.4 ScanningTunnelingMicroscopy(STM) . . . . . . . . . . . . . . . . . . . 47
7.5 Bufferlayerpreparationandcharacterization: AtomicForceMicroscopy . . 48
7.6 SecondaryIonMassSpectrometry(SIMS) . . . . . . . . . . . . . . . . . . 52
7.7 ElasticRecoilDetection(ERD) . . . . . . . . . . . . . . . . . . . . . . . . 53
8 FETconceptsbasedonBoronδ Doping 57
8.1 MESFETCharacteristicsandStructure . . . . . . . . . . . . . . . . . . . . 57
8.2 P I PFET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
8.3 MESFETandMOSFETStructuresappliedtoDiamond . . . . . . . . . . . 61
8.4 δ ChannelFET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
8.5 IonSensitiveFETonDiamond . . . . . . . . . . . . . . . . . . . . . . . . 64
IICONTENTS
9 TechnologyandFabricationProcess 69
9.1 TechnologicalSteps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
9.1.1 OhmiccontactTechnology . . . . . . . . . . . . . . . . . . . . . . 70
9.1.2 Gatecontacttechnology . . . . . . . . . . . . . . . . . . . . . . . 73
9.1.3 Gaterecess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
9.1.4 Mesaetching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
9.1.5 Recessetchingandovergrowth . . . . . . . . . . . . . . . . . . . . 74
9.2 SingledeltaMISFET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
9.3 Doubledeltalayertransistors . . . . . . . . . . . . . . . . . . . . . . . . . 79
9.4 DoubledeltaFETswithdielectriclayerpriortometalization . . . . . . . . 80
9.5 ISFETonSinglecrystalDiamond . . . . . . . . . . . . . . . . . . . . . . 82
10 Results 85
10.1 Doubledeltatransistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
10.2 SingledeltaMISFET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
10.3 SingleCrystalISFETresults . . . . . . . . . . . . . . . . . . . . . . . . . 94
10.4 P I PTransistorResults . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
11 Conclusionandoutlook 101
A ISFETonNCDusingDeltaDoping 103
A.1 NanoCrystallineHFCVDdiamondfilmson4inchSiliconwafers . . . . . 103
A.2 ISFET onNanocrystallineDiamond . . . . . . . . . . . . . . . . . . . . 105
A.2.1 DeltadopedNanodiamond . . . . . . . . . . . . . . . . . . . . . . 105
A.2.2 NanodiamondISFETfabrication . . . . . . . . . . . . . . . . . . . 106
A.3 NanoCrystallineISFETResults . . . . . . . . . . . . . . . . . . . . . . . 108
A.4 ConclusionfortheISFET . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
B TransmissionElectronMicroscopyStudy 113
B.0.1 SamplePreparation . . . . . . . . . . . . . . . . . . . . . . . . . . 113
B.0.2 TEMStudy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
IIICONTENTS
C TechnologicalProcesses 121
C.1 SamplesCleaningProcess . . . . . . . . . . . . . . . . . . . . . . . . . . 121
C.2 GrowthParameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
C.3 DryEtchingProcess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
C.4 OpticalLithographyProcess . . . . . . . . . . . . . . . . . . . . . . . . . 122
C.5 E BeamyProcess . . . . . . . . . . . . . . . . . . . . . . . . . 123
C.6 OxygenTerminationofthediamondsurface . . . . . . . . . . . . . . . . . 123
C.7 RapidThermalAnnealingoftheOhmiccontacts . . . . . . . . . . . . . . 124
C.8 MobilityMeasurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
D ListofSymbols 127
E Bibliography 131
IVListofFigures
2.1 Powerandfrequencycapabilitiesofdifferentsemiconductors. . . . . . . . 6
3.1 Face centeredcubiclatticeofdiamondwiththelatticeconstant a = 3.566Å 9
3.2 Thebandstructureofdiamondafter[1]. . . . . . . . . . . . . . . . . . . . 10
4.1 Thecarbonphasediagram. After[2] . . . . . . . . . . . . . . . . . . . . . 15
4.2 AschematicdiagramoftheHTHPcell. after[3] . . . . . . . . . . . . . . . 16
−14.3 Ramanspectraof4differentintrinsicCVDlayersshowingthetypical1332cm
−1peakwithawidthof2cm . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.4 SchematicsoftheprocessesoccurringduringdiamondCVDgrowth. . . . . 20
4.5 SchematicoftheroleofatomichydrogeninthediamondCVDgrowth. . . 20
4.6 HTHP stones with a diamond film epitaxially grown on top. The substrate
onthebottomrightcornerhasFETsfabricatedonit. . . . . . . . . . . . . 23
5.1 Schematicdopingconfigurationofphosphorous,nitrogenandborondoping
indiamond. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.2 Cathodoluminescence spectra of 5 nitrogen doped thick layers with differ-
entnitrogentomethaneconcentrations. (measuredbyG.Prince,Semicon
ductorPhysicsDepartment,UlmUniversity.) . . . . . . . . . . . . . . . . 29
5.3 Hydrogen inducedp−type channel. The origin of the acceptors is still un
clear[4]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.1 SimplifiedschematicoftheMWPCVDmachineusedintheδ−dopingpro
cess. Tobenoticedisthesolidboronsourceintroducedintheplasmaball. . 34
6.2 Linear cyclic voltametry scan of boron delta doped layer on the surface of
(100) oriented diamond substrate in 0.1MH SO electrolyte. The scan2 4
ratewas50mV/s,asshownlateroninFigure8.9a). . . . . . . . . . . . . 36
6.3 The acceptor profile of a single boron delta doped layer extracted from
capacitance voltage characteristics of the diamond electrolyte junction in
0.1MH SO at 1.0kHz oscillation frequency. The dashed curve shows2 4
the Gaussian profile calculated for the Debye length, corresponding to the
21 3peakconcentrationof10 1/cm electrolyte. . . . . . . . . . . . . . . . . 37
VLIST OF FIGURES
6.4 Adepthprofileofadeltadopedlayershowingthedopingprofilealongwith
theactualcarrierprofile. . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
6.5 Typical epitaxial cycle of the growth used for the fabrication of a double
deltatransistordesign. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
7.1 4PLspectraofthedeltalayersshowingaweekboronrelatedpeak. (mea
suredbyG.Prince,SemiconductorPhysicsDepartment,UlmUniversity) . 44
7.2 AtypicalTLMmeasurementofasingledeltalayer. . . . . . . . . . . . . . 45
7.3 A typical window of a cyclic voltametry measurement on single crystal
diamond, showing a 3V water dissociation window. (Measured by A.
Denisenko). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7.4 FreecarrierprofilingC−V measurementshowingtheindependenceofthe
measurementontheappliedfrequency. (MeasuredbyA.Denisenko). . . . 46
7.5 Debye tails plotted along aC−V measurement of a delta layer, matching
verywelltoeachother. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
27.6 STM scan of 10× 10nm area of a boron doped delta layer, where no
boronclusterscouldbeidentified. . . . . . . . . . . . . . . . . . . . . . . 48