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