Table Of ContentIraj Sadegh Amiri · Hossein Mohammadi
Mahdiar Hosseinghadiry
Device Physics,
Modeling,
Technology, and
Analysis for Silicon
MESFET
Device Physics, Modeling, Technology,
and Analysis for Silicon MESFET
(cid:129)
Iraj Sadegh Amiri Hossein Mohammadi
Mahdiar Hosseinghadiry
Device Physics, Modeling,
Technology, and Analysis
for Silicon MESFET
IrajSadeghAmiri HosseinMohammadi
ComputationalOpticsResearchGroup PasargadHigherEducationInstitute
AdvancedInstituteofMaterialsScience Shiraz,Iran
TonDucThangUniversity
HoChiMinhCity,Vietnam
FacultyofAppliedSciences
TonDucThangUniversity
HoChiMinhCity,Vietnam
MahdiarHosseinghadiry
AllseasEngineering
DELFT,Zuid-Holland,TheNetherlands
ISBN978-3-030-04512-8 ISBN978-3-030-04513-5 (eBook)
https://doi.org/10.1007/978-3-030-04513-5
LibraryofCongressControlNumber:2018964064
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Preface
In the recent years, silicon-on-insulator metal-semiconductor field effect transistor
(SOIMESFET)hasattractedextensiveattentionduetoitsbettermobilitydegrada-
tion, scalability, isolation between source-drain and substrate, immunity to hot
carrier effect (HCE), and radiation hardness. However, creative approaches are
needed to overcome the problems associated with downscaling. In this research,
twonoveldesignsofSOIMESFETarepresentedtoimprovethechannelmobility,
threshold voltage roll-off, immunity against short channel effects (SCE), and scal-
ability.Inthefirstdesign,TMGSOIMESFET,threedifferentmetalswithdifferent
work functions are used as a singular gate metal. Due to this technique, two step
functions appear in the profile ofpotential which causes two potential drops in the
channel.Accordingly,thechannelisscreenedfromthevariationsofdrainvoltageto
getbettercarriertransportandmorescalability.Inaddition,thelocationofminimum
potential moves toward the source and, in turn, protection against drain-induced
barrier lowering (DIBL) is found. In the second design, TG SOI MESFET, better
currentcontrolisgainedbyextendingofgatemetaltothesidewallsofthechannel.
This provides higher current drive, more immunity against SCEs, and further
scalability. Analytical modeling and TCAD simulation for the classical SOI
MESFET and the two proposed designs have been developed. The profiles of
channel potential for the devices under study show the slope of bottom potential
(ΔΦ/Δx)tothedrainsideatthebiasconditionofV ¼0.5VforTMGMESFET
DS
andTGMESFETas0.6V/μmand0.4V/μm,respectively,whicharemuchsmaller
thanfortheclassicalMESFETwithaslopeof1.3V/μm.Itimpliesthattheproposed
devicescaneffectivelyreducetheelectricfieldnearthedrainsideandrelatedshort
channel effects. Moreover, from the profile of threshold voltage, the threshold
voltage roll-off in the classical device does not differ noticeably from that the
proposed designs for longer channel gates. However, for classical SOI MESFET,
the threshold voltage roll-off becomes considerable for channel lengths less than
250nm.ThesesimilarvaluesforTMGandTGMESFETsare130nmand50nm,
respectively.Itindicatesthefurtherscalabilityoftheproposeddesigns.Finally,for
thegatelengthof100nm,DIBLfromthevalueof300mV/V,intheclassicaldevice,
v
vi Preface
reducestothevaluesof70and30mV/VforTMGandTGMESFET,respectively.
This indicates that using the proposed designs of SOI MESFET, better control of
DIBLisobtained.
HoChiMinhCity,Vietnam IrajSadeghAmiri
Shiraz,Iran HosseinMohammadi
Delft,TheNetherlands MahdiarHosseinghadiry
Contents
1 InventionandEvaluationofTransistorsandIntegrated
Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 ResearchBackground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 TheHistoryofTransistor. . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.2 IntegratedCircuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1.3 InternationalTechnologyRoadmapforSemiconductors. . 4
1.2 ProblemStatement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3 ObjectiveofResearchandScopeofWork. . . . . . . . . . . . . . . . . 7
1.4 BookOrganization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2 GeneralOverviewoftheBasicStructureandOperation
ofaTypicalSilicononInsulatorMetal–Semiconductor
FieldEffectTransistor(SOI-MESFET). . . . . . . . . . . . . . . . . .. . . . . 11
2.1 BasicsofSOI-MESFET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 CMOSScaling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2.1 ConstantFieldScaling. . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2.2 ConstantVoltageScaling. . . . . . . . . . . . . . . . . . . . . . . . 15
2.3 Short-ChannelEffectsAssociatedwithDeviceScaling. . . . . . . . 16
2.3.1 Drain-InducedBarrierLoweringandPunch-through. . . . . 16
2.3.2 HotCarrierEffect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3.3 ImpactIonization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3.4 ChannelLengthModulation. . . . . . . . . . . . . . . . . . . . . . 18
2.3.5 SurfaceScattering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.3.6 VelocitySaturationofCarriers. . . . . . . . . . . . . . . . . . . . 19
2.4 QuantumMechanicalEffect[11]. . . . . . . . . . . . . . . . . . . . . . . . 20
2.5 TechnicalSolutionsforFurtherScalingofMOSDevices. . . . . . 20
2.6 Architecture-BasedNon-classicalDevices. . . . . . . . . . . . . . . . . 21
2.6.1 Silicon-On-Insulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.6.2 DeviceswithMultipleGates. . . . . . . . . . . . . . . . . . . . . . 24
vii
viii Contents
2.7 Material-BasedNon-CLASSICALDevices.. . . . . . .. . . . . . . .. 28
2.7.1 High-kMetalGateStackMOSFETs. . . . . . . . . . . . . . . . 29
2.7.2 StrainedMOSFETs. . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.7.3 DualMaterialGate(DMG)MOSFETs. . . . . . . . . . . . . . 31
2.8 FutureGenerationDevices. . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.9 ABriefReviewofthePreviousWorks. . . . . . . . . . . . . . . . . . . . 32
2.9.1 TheRelatedWorksonMOSFETs. . . . . . . . . . . . . . . . . . 33
2.9.2 TheRelatedWorksonSiliconMESFETs. . . . . . . . . . . . 36
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3 ModelingofClassicalSOIMESFET. . . . . . . . . . . . . . . . . . . . . . . . . 43
3.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.2 DescriptionofDeviceStructure. . . . . . . . . . . . . . . . . . . . . . . . . 44
3.3 DefinitionoftheProblem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.3.1 CalculationofChannelPotential. . . . . . . . . . . . . . . . . . . 46
3.3.2 DefinitionofThresholdVoltage. . . . . . . . . . . . . . . . . . . 53
3.3.3 DefinitionofSubthresholdCurrentandSubthreshold
Swing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.4 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4 DesignandModelingofTriple-MaterialGateSOIMESFET. . . . . . 59
4.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.2 DescriptionoftheDeviceStructure. . . . . . . . . . . . . . . . . . . . . . 60
4.3 PotentialDistribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
4.3.1 MathematicalApproach. . . . . . . . . . . . . . . . . . . . . . . . . 61
4.3.2 BoundaryConditions. . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.3.3 SolutionofVi(y). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4.3.4 SolutionofUi(x,y). . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.4 DefinitionofThresholdVoltage. . . . . . . . . . . . . . . . . . . . . . . . . 69
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
5 Three-DimensionalAnalyticalModeloftheNon-Classical
Three-GateSOIMESFET. . . .. . . .. . . .. . . .. . . .. . . .. . . .. . . .. 73
5.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.2 DeviceStructure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.3 DefinitionofChannelPotential. . . . . . . . . . . . . . . . . . . . . . . . . 74
5.3.1 BoundaryConditions. . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.3.2 1-DPoisson’sEquationforФ1D(y). . . . . . . . . . . . . . . . . 77
5.3.3 2-DLaplace’sEquationforФ2D(x,y). . . . . . . . . . . . . . . . 78
5.3.4 3-DLaplace’sEquationforФ3D(x,y,z). . . . . . . . . . . . . . . 83
5.4 DefinitionoftheThresholdVoltage. . . . . . . . . . . . . . . . . . . . . . 89
5.5 DefinitionoftheSubthresholdSwing. . . . . . . . . . . . . . . . . . . . . 91
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Contents ix
6 AnalyticalInvestigationofSubthresholdPerformance
ofSOIMESFETDevices. . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 93
6.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
6.2 AnalysisofShort-ChannelSOIMESFET. . . . . . . . . . . . . . . . . . 93
6.2.1 DeviceDimensionandParameters. . . . . . . . . . . . . . . . . 94
6.2.2 AnalysisoftheChannelPotential. . . . . . . . . . . . . . . . . . 94
6.2.3 AnalysisofThresholdVoltage. . . . . . . . . . . . . . . . . . . . 96
6.2.4 AnalysisofDIBL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6.2.5 AnalysisofSubthresholdCurrentandSubthreshold
Swing. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
6.3 AnalysisofTriple-MaterialGateSOIMESFET. . . . . . . . . . . . . 101
6.3.1 DeviceParametersandDimensions. . . . . . . . . . . . . . . . . 102
6.3.2 AnalysisoftheChannelPotential. . . . . . . . . . . . . . . . . . 102
6.3.3 AnalysisofThresholdVoltage. . . . . . . . . . . . . . . . . . . . 105
6.3.4 AnalysisofSubthresholdSwing. . . . . . . . . . . . . . . . . . . 106
6.4 AnalysisofThree-GateSOIMESFET. . . . . . . . . . . . . . . . . . . . 107
6.4.1 AnalysisoftheChannelPotential. . . . . . . . . . . . . . . . . . 107
6.4.2 AnalysisoftheThresholdVoltage. . . . . . . . . . . . . . . . . 109
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
7 FutureWorksonSilicon-on-InsulatorMetal–Semiconductor
FieldEffectTransistors(SOIMESFETs). . . . . . . . . . . . . . . . . . . . . 113
7.1 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
7.1.1 FullyDepletedShort-ChannelSOIMESFET. . . . . . . . . . 114
7.1.2 NewDesignTri-MaterialGate(TMG)SOIMESFET. . . . 114
7.1.3 NewDesignThree-Gate(TG)SOIMESFET. . . . . . . . . . 115
7.2 FutureScopeoftheWork. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Appendix:TheWorkFunctionsoftheCommonMetals. . . . . . . . . . . . . 117
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Chapter 1
Invention and Evaluation of Transistors
and Integrated Circuits
1.1 Research Background
1.1.1 The History of Transistor
In the early years of the emergence of the electronics industry, electron tubes, or
vacuum tubes, were the basis of almost all electronic devices. Electron tube is an
electronic device that controls transmission of electrons between two metal elec-
trodesthroughthevacuumorgaswithinagastightcontainermadeofglassormetal.
Electron tubes mostly rely on thermionic emission of electrons provided by a hot
filamentoracathodeheatedbythefilament.Theprimaryapplicationofthisdeviceis
toamplifyweakcurrentsoroperateasaone-wayrectifierforelectriccurrent[1].
In1925,theideaofcontrollingthecurrentflowbyaperpendicularelectricfield,
whattodayweknowasmetal–semiconductorFET(MESFET),wasplannedforthe
firsttimebyLilienfeldin1925.Herecordedapatentontheinventionofthetransistor
in 1930 as a replacement for the electron tube, but he did not publish any paper
regarding this invention [2]. However, due to the technical problems, the MEFET
couldnotbesuccessfullyfabricatedatthattimeandwasignoredbytheindustryfor
many years [3]. Nine years after Lilienfeld, Oskar Heil followed the Lilienfeld’s
researchandrecordedanotherpatentforthefieldeffecttransistor[4].Afterwards,it
hasbeendemonstratedthatLilienfeld’stransistorgavebetterresultsandgain[5].
In 1938, Schottky made a theory that described the rectifying behavior of a
metal–semiconductorcontactasdependentonabarrierlayeratthesurfaceofcontact
between the two materials [6]. The metal–semiconductor diodes later made on the
basisofthistheoryarecalledSchottkybarrierdiodes.
In1947,aresearchteamattheBellLaboratoriesincludingJohnBardeen,Walter
Brattain,andWilliamShockleyobservedthatelectricpowergainisobtainedwhen
anarrangementofspringsandwiresareconnectedtoasmallcrystalofgermanium
[7]. Using this observation, they made the first bipolar junction transistor (BJT).
This transistor was constituted from two gold wires which were very closely
©SpringerNatureSwitzerlandAG2019 1
I.S.Amirietal.,DevicePhysics,Modeling,Technology,andAnalysisforSilicon
MESFET,https://doi.org/10.1007/978-3-030-04513-5_1
