m,w,f 12:00-12:50 (x), 2015 eceb 2114 micro and ...€¦ · 13. calculate the contact potential of...
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M,W,F12:00-12:50(X),2015ECEBProfessorJohnDallesasse
DepartmentofElectricalandComputerEngineering2114MicroandNanotechnologyLaboratory
Tel:(217)333-8416E-mail:jdallesa@illinois.edu
OfficeHours:Wednesday13:00–14:00
TentativeSchedule[1]
JAN17Courseoverview
JAN19Introtosemiconductorelectronics
JAN22Materialsandcrystalstructures
JAN24Bondingforcesandenergybandsinsolids
JAN26Metals,semiconductors,insulators,electrons,holes
JAN29Intrinsicandextrinsicmaterial
JAN31Distributionfunctionsandcarrierconcentrations
FEB2Distributionfunctionsandcarrierconcentrations
FEB5Temperaturedependence,compensation
FEB7Conductivityandmobility
FEB9Resistance,temperature,impurityconcentration
FEB12InvarianceofFermilevelatequilibrium
FEB14Opticalabsorptionandluminescence
FEB16Generationandrecombination
2 **Subject to Change**
Today’sDiscussion
• GeneralIntroductiontoSemiconductorElectronics
• CrystalStructures• Assignments• TopicsforNextLecture
3
PeriodicTableoftheElementsIV V III
II
VI
ImportantMaterialSystems• ElementalSemiconductors
– Silicon• ICs,CCDs,SolarPanels&SolarCells
– Germanium• SubstratesforHigh-EfficiencySolarCells,LongWavelengthPhotodetectors
• BinarySemiconductors– SiGe
• HighSpeedElectronics– InP
• OpticalCommunicationDevices,HighSpeedElectronics– GaAs
• WirelessCommunications,Short-DistanceOpticalLinks– GaN
• LEDsforLighting,HighTemperatureElectronics
6
ImportantMaterialSystems
• TernarySemiconductors– AlGaAs:VCSELsforShort-ReachLinks,DPSSLPumpLasers– InGaAsonInP:HighSpeedPhotodiodes,LongWavelengthCameras
– StrainedAlGaAs/InGaAsonGaAs:980nmPumpLasersforEDFAs
– GaAsP:CommodityRedLEDs– InGaN:BlueLEDs
• QuaternarySemiconductors– InGaAsPonInP,InAlGaAsonInP:OpticalCommunications(1310&1550nm)
– InGaAsPonGaAs(LasersforDPSSL),InAlGaP7
OtherMaterials• IV
– SiC:Pre-GaNBlueLEDs,PowerElectronicDevices• III-VMaterials
– InAs:IRPhotodetectors– GaInNAs:Materialstudiedfor1310/1550nmonGaAs
• II-VIMaterials– ZnSe:Pre-GaNBlueLEDs,Scintillators– CdTe:SolarCells– HgCdTe:SolarCells,Mid-IRDetectors– InSe:Photovoltaics– ZnS,CdS,ZnCdS:CRTPhosphors
• Other– IndiumTinOxide(ITO):TransparentConductors
8
BandgapandLatticeConstantofCommonSemiconductors
9
BasicEquationsforSemiconductorDeviceOperation
• Thebasicequationsforsemiconductordeviceoperationdescribethestaticanddynamicbehaviorofcarriersinsemiconductorsundertheinfluenceofexternalfieldsthatcausedeviationfromthethermalequilibriumconditions
• Thebasicequationscanbeclassifiedinfourgroups:– Maxwell’sEquations,– Current-DensityEquations,– ContinuityEquations,and– QuantumMechanics&Shrödinger’sEquation
11
MaxwellEquationsforHomogeneousandIsotropicMaterials
E: electric field D: electric displacement B: magnetic field H: magnetizing field : permittivity : permeability : total electric charge
density Jcond: the conduction
current density P: polarization density ×: curl operator �: divergence operator
∇× E = − ∂B∂t
∇× H = − ∂D∂t
+ Jcond = Jtotal
∇•D = ρ(x, y, z)∇• B = 0B = µoH
D(r,t) = ε s (t − t' )E(r,t ' )dt '
−∞
t
∫ = εE + P
sεoµ
ρ
12
KeyPoints:Fields&Waves
Charge creates divergence in the electric displacement field: ∇ iD = ρ
The electric field is related to the electric displacement fieldthrough the permittivity: D = εE
The electric field is the negative of the gradient of the scalar potential field: E = −∇V
In one dimesion: E (x) = − dV (x)dx
V (x) = − E (x)dx∫
http://www.pstcc.edu/departments/natural_behavioral_sciences/Web%20Physics/E2020D0103.gif
13
Gauss’Law
• Thedivergenceoftheelectricdisplacementfluxdensityisequaltothechargedensity
• CanbederivedfromAmpere’sLawusingtheContinuityEquation
∇•D = ρ
ρ is the charge density with units of Coulombsm3
http://www.ibiblio.org/links/devmodules/Gauss/graphics/blob1.gif
14
KeyPoints:CircuitConceptsCapacitance :
Simple Form: C = QV
Differential Form: C = dQdV
Resistance / Conductance : Ohm's Law: V = IR
Resistance (AC): R = dVdI
Conductance (AC): G = dIdV
Bulk Resistivity: ρ = R AL= 1σ
Loop Analysis
Node Analysis
http://mathonweb.com/help/backgd4.htm
i1 + i4 = i2 + i3
1i1 + 25 i1 − i2( ) + 50 i1 − i3( )−10 = 025 i2 − i1( ) + 30i2 +1 i2 − i3( ) = 050 i3 − i1( ) +1 i3 − i2( ) + 55i3 = 0
⎧
⎨⎪
⎩⎪
I = JA
I = VR=σ AV
L Ohms Law
R = 1σLA= ρ L
A15
Current-DensityEquations
• Insemiconductor,inadditiontoanelectroncurrentdensitythereisaholecurrentdensity
• Eachcurrentconsistofthedriftcomponentcausebyfieldandthediffusioncomponentcausedbythecarrierconcentrationgradient
pncond
ppp
nnn
JJJpqDpEqJnqDnEqJ
+=
∇−=∇+=
µµ
Drift Diffusion
16
ContinuityEquations
ppp
nnn
Jq
UGtp
Jq
UGtn
•∇−−=∂∂
•∇+−=∂∂
1
1
For a given volume of semiconductor, the rate change of carrier is the net effect of current flow into the volume and generation and recombination rates within the volume. : electron generation rate : hole generation rate : electron recombination rate : hole recombination rate
nGpGnUpU 17
QuantumMechanics
Heisenberg Uncertainty Principle : Position-Momentum: Δx i Δpx( ) ≥ / 2
Energy-Time: ΔE i Δt( ) ≥ / 2Schrodinger's Equation :
− 2
2m∇2Ψ +VΨ = −
j∂Ψ∂t
(Kinetic Energy + Potential Energy = Total Energy)
Ψ(x, y, z,t) is continuous, finite, and single-valued The derivative in space of Ψ(x, y, z,t) is continuous, finite, and single-valuedThe probability of finding a particle with wave function Ψ is Ψ*Ψ
The particle is somewhere, so Ψ*Ψdxdydz = 1−∞
∞
∫The expectation value of an operator Q is: Q = Ψ*QopΨdxdydz
−∞
∞
∫18
Assignments
• Readinfopacket–keycoursepoliciesandscheduleareoutlinedhere,includinghourlyexamdates
• HomeworkassignedeveryFriday,duefollowingFriday
• BegintoreadChapter1ofStreetman’sbook– Sections1.1,1.2,1.3.1,1.4– IsuggestreadingallofChapter1,butonlytheabovesectionsareassigned
• Chapter1inPierretcoverssimilarmaterial,andcomplementsStreetmanforanotherperspective
20
Outline,1/22/18
• Finishintroductiontosemiconductorelectronics• Commonsemiconductorcrystalstructures• Latticeconstants• Millerindices• Examples:
– DeterminingMillerindicesforvariouscrystalplanes– Densitycalculations
• Epitaxialgrowthtechnologies
22
InstructionalObjectives(1)BythetimeofexamNo.1(after17lectures),thestudentsshouldbeabletodothefollowing:1.Outlinetheclassificationofsolidsasmetals,semiconductors,andinsulatorsanddistinguishdirectandindirectsemiconductors.2.DeterminerelativemagnitudesoftheeffectivemassofelectronsandholesfromanE(k)diagram.3.Calculatethecarrierconcentrationinintrinsicsemiconductors.4.ApplytheFermi-Diracdistributionfunctiontodeterminetheoccupationofelectronandholestatesinasemiconductor.5.CalculatetheelectronandholeconcentrationsiftheFermilevelisgiven;determinetheFermilevelinasemiconductorifthecarrierconcentrationisgiven.6.Determinethevariationofelectronandholemobilityinasemiconductorwithtemperature,impurityconcentration,andelectricalfield.7.Applytheconceptofcompensationandspacechargeneutralitytocalculatetheelectronandholeconcentrationsincompensatedsemiconductorsamples.8.Determinethecurrentdensityandresistivityfromgivencarrierdensitiesandmobilities.9.Calculatetherecombinationcharacteristicsandexcesscarrierconcentrationsasafunctionoftimeforbothlowlevelandhighlevelinjectionconditionsinasemiconductor.10.Usequasi-Fermilevelstocalculatethenon-equilibriumconcentrationsofelectronsandholesinasemiconductorunderuniformphotoexcitation.11.Calculatethedriftanddiffusioncomponentsofelectronandholecurrents.12.CalculatethediffusioncoefficientsfromgivenvaluesofcarriermobilitythroughtheEinstein’srelationshipanddeterminethebuilt-infieldinanon-uniformlydopedsample.
https://my.ece.illinois.edu/courses/description.asp?ECE340 24
InstructionalObjectives(2)BythetimeofExamNo.2(after32lectures),thestudentsshouldbeabletodoalloftheitemslistedunderA,plusthefollowing:13.Calculatethecontactpotentialofap-njunction.14.Estimatetheactualcarrierconcentrationinthedepletionregionofap-njunctioninequilibrium.15.Calculatethemaximumelectricalfieldinap-njunctioninequilibrium.16.Distinguishbetweenthecurrentconductionmechanismsinforwardandreversebiaseddiodes.17.Calculatetheminorityandmajoritycarriercurrentsinaforwardorreversebiasedp-njunctiondiode.18.Predictthebreakdownvoltageofap+-njunctionanddistinguishwhetheritisduetoavalanchebreakdownorZenertunneling.19.Calculatethechargestoragedelaytimeinswitchingp-njunctiondiodes.20.Calculatethecapacitanceofareversebiasedp-njunctiondiode.21.Calculatethecapacitanceofaforwardbiasedp-njunctiondiode.22.Predictwhetherametal-semiconductorcontactwillbearectifyingcontactoranohmiccontactbasedonthemetalworkfunctionandthesemiconductorelectronaffinityanddoping.23.Calculatetheelectricalfieldandpotentialdropacrosstheneutralregionsofwidebase,forwardbiasedp+-njunctiondiode.24.Calculatethevoltagedropacrossthequasi-neutralbaseofaforwardbiasednarrowbasep+-njunctiondiode.25.Calculatetheexcesscarrierconcentrationsattheboundariesbetweenthespace-chargeregionandtheneutraln-andp-typeregionsofap-njunctionforeitherforwardorreversebias.
https://my.ece.illinois.edu/courses/description.asp?ECE340 25
InstructionalObjectives(3)BythetimeoftheFinalExam,after44classperiods,thestudentsshouldbeabletodoalloftheitemslistedunderAandB,plusthefollowing:26.CalculatetheterminalparametersofaBJTintermsofthematerialpropertiesanddevicestructure.27.Estimatethebasetransportfactor“B”ofaBJTandrank-ordertheinternalcurrentswhichlimitthegainofthetransistor.28.DeterminetherankorderoftheelectricalfieldsinthedifferentregionsofaBJTinforwardactivebias.29.CalculatethethresholdvoltageofanidealMOScapacitor.30.PredicttheC-VcharacteristicsofanMOScapacitor.31.CalculatetheinversionchargeinanMOScapacitorasafunctionofgateanddrainbiasvoltage.32.EstimatethedraincurrentofanMOStransistorabovethresholdforlowdrainvoltage.33.EstimatethedraincurrentofanMOStransistoratpinch-off.34.DistinguishwhetheraMOSFETwithaparticularstructurewilloperateasanenhancementordepletionmodedevice.35.Determinetheshort-circuitcurrentandopen-circuitvoltageforanilluminatedp/njunctionsolarcell.
https://my.ece.illinois.edu/courses/description.asp?ECE340 26
CoursePurpose&Objectives
• Introducekeyconceptsinsemiconductormaterials
• Provideabasicunderstandingofp-njunctions
• Provideabasicunderstandingoflight-emittingdiodesandphotodetectors
• Provideabasicunderstandingoffieldeffecttransistors
• Provideabasicunderstandingofbipolarjunctiontransistors
n-type emitter n-type collector
p-type base
ForwardBias
ReverseBias
electron flow
hole flowleakagecurrent
injectedelectrons
injectedholes
27
TentativeSchedule[2]
FEB19Quasi-Fermilevelsandphotoconductivedevices
FEB21Carrierdiffusion
FEB23Built-infields,diffusionandrecombination
Feb26Review,discussion,problems(2/27exam)
FEB28Steadystatecarrierinjection,diffusionlength
MAR2p-njunctionsinequilibrium&contactpotential
MAR5p-njunctionFermilevelsandspacecharge
MAR7Continuep-njunctionspacecharge
MAR9NOCLASS(EOH)
MAR12p-njunctioncurrentflow
MAR14Carrierinjectionandthediodeequation
MAR16Minorityandmajoritycarriercurrents
3/19-3/23SpringBreakMAR26Reverse-biasbreakdown
MAR28Storedcharge,diffusionandjunctioncapacitance
MAR30Photodiodes,I-Vunderillumination
28 **Subject to Change**
TentativeSchedule[3]
APR2LEDsandDiodeLasers
APR4Metal-semiconductorjunctions
APR6MIS-FETs:Basicoperation,idealMOScapacitor
APR9MOScapacitors:flatband&thresholdvoltage
APR11Review,discussion,problems(4/12exam)
APR13MOScapacitors:C-Vanalysis
APR16MOSFETs:Output&transfercharacteristics
APR18MOSFETs:smallsignalanalysis,amps,inverters
APR20Narrow-basediode
APR23BJTfundamentals
APR25BJTspecifics
APR27BJTnormalmodeoperation
APR30BJTcommonemitteramplifierandcurrentgain
MAY2(LASTLECTURE)Review,discussion,problemsolving
FINALEXAM**Date&timetobeannounced**
29 **Subject to Change**
ImportantInformation
• CourseWebsite:– http://courses.engr.illinois.edu/ece340/
• DownloadandReviewSyllabus/CourseInformationfromWebsite!• CourseCoordinator:Prof.JohnDallesasse
– jdallesa@illinois.edu– Coordinatesschedule,policies,absenceissues,homework,quizzes,
exams,etc.• ContactInformationandOfficeHoursforAllECE340Professors&
TAsinSyllabus• LectureSlides:Clickon“(Sec.X)”nexttomynameininstructorlist• DRESStudents:ContactProf.DallesasseASAP• Textbook:
– “SolidStateElectronicDevices,”Streetman&Banerjee,7thEdition– Supplemental:“SemiconductorDeviceFundamentals,”Pierret– Additionalreferencetextslistedinsyllabus
31
KeyPoints
• AttendClass!– 3unannouncedquizzes,eachworth5%ofyourgrade– Youmusttakethequizinyoursection– Excusedabsencesmustbepre-arrangedwiththecoursedirector– Absencesforillness,etc.needanotefromtheDean
• Seepolicyonabsencesinthesyllabus• NoLateHomework
– Homeworkdueonthedateofanexcusedabsencemustbeturnedinaheadoftime
– Youmustturninhomeworkinyoursection– Noexcusedabsencesforhomeworkassignments– Top10of11homeworkassignmentsusedincalculationofcoursegrade
• Doallofthemtobestpreparefortheexams!• NoCheating
– Penaltiesaresevereandwillbeenforced• TurnOffYourPhone
– Novideorecording,audiorecording,orphotography
32
Homework
• AssignedFriday,DueFollowingFriday– Duedatesshowninsyllabus
• DueatStartofClass• FollowGuidelinesinSyllabus• PeerDiscussionsRelatedtoHomeworkareAcceptableandEncouraged
• DirectlyCopyingSomeoneElse’sHomeworkisNotAcceptable– Gradershavebeeninstructedtowatchforevidenceofplagiarism
– Bothpartieswillreceivea“0”ontheproblemorassignment
33
Absences
• Theabsencepolicyinthesyllabuswillbestrictlyenforced• Toreceiveanexcusedabsence(quiz),youmust:
– Pre-arrangetheabsencewiththecoursedirector(validreasonandproofrequired)
– CompleteanExcusedAbsenceFormattheUndergraduateCollegeOffice,Room207EngineeringHall(333-0050)
• Theformmustbesignedbyaphysician,medicalofficial,ortheEmergencyDean(OfficeoftheDeanofStudents)
• TheDean’sOfficehasrecentlyputastrictpolicyinplace(3documenteddaysofillness)– Excusedquizscorewillbeproratedbaseduponaverageofcompletedscores– Noexcusedabsencesaregivenforhomework,butonlythebest10of11are
usedtocalculateyourfinalgrade– Excusedabsencesarenotgivenforexams,exceptinaccordancewiththe
UIUCStudentCode– Unexcusedworkwillreceivea“0”
• Failuretotakethefinalwillresultinan“incomplete”grade(ifexcused)ora“0”(ifunexcused)
34
Exams
• ExamI:TuesdayFebruary27th,7:30-8:30pm• ExamII:ThursdayApril12th,7:30-8:30pm• FinalExam:Date/TimeToBeAnnounced
– DeterminedbyUniversityF&S
35
Grading
GradingCriterion
Homework 10%
Quizzes 15%
HourExamI 20%
HourExamII 20%
FinalExam 35%
Total 100%
HistoricalGradeTrends*
Spring2016
Fall2016
Spring2017
A’s 27% 28% 27%
B’s 37% 26% 38%
C’s 27% 25% 27%
D’s 6% 16% 4%
F’s 3% 5% 4%
*Past performance is not necessarily indicative of future results
36
MyRecommendations
• Readthesyllabusandinformationpostedonthecoursewebsite
• Attendclass&participate• Attendofficehours(TAandProfessors)• Readthebook• Re-readthebook• Lookatandreadselectedportionsofthesupplemental
texts• Formstudygroupstoreviewconceptsanddiscusshigh-
levelapproachesforsolvinghomeworkproblems– Don’tformstudygroupstocopyhomeworksolutions
• Don’tmissanyhomework,quizzes,orexams• It’shardtoovercomeazero
• Askquestionsinclass!37
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