微專(zhuān)業(yè)---半導(dǎo)體制造技術(shù)課程：半導(dǎo)體工程專(zhuān)業(yè)英語(yǔ)ContentsSemiconductorProperties半導(dǎo)體特性01SemiconductorMaterials半導(dǎo)體材料02SemiconductorDeviceandHowTheyareUsed半導(dǎo)體器件及其使用03ProcessTechnology工藝技術(shù)04FabricationProcesses制造工藝05SemiconductorMaterialsandProcessCharacterization半導(dǎo)體材料與工藝表征06SemiconductorProperties1.1ElectricalConductivityofSolids1.2ElectricChargeCarriers1.3SemiconductorsandExternalInfluences1.4SemiconductorsinNanoscale011

SemiconductorProperties1ChapterOverview

Thegoalofthischapteristoconsiderinqualitativetermsfundamentalpropertiesofsolidsknownassemiconductors.Thediscussionisnotmeanttobeastructuredoverviewofthephysicsofsemiconductors,butratherasimplifiedreviewaimedattheidentificationofthosepropertiesofthisclassofmaterialswhichareessentialtotheunderstandingoftheprinciplesuponwhichfunctionalsemiconductordevicesarebuiltandoperate./?kwɑ?l?te?t?v/定性的/?s?mpl?fa?d/簡(jiǎn)化的/s?mik?n?d?kt?rz/半導(dǎo)體器件2Introduction

Theextenttowhichasolidisabletoconductelectricityisacharacteristic

definingitsusefulnessintherangeofpracticalapplications.Inthissection

atomic-levelfeaturesdefiningelectricalconductivityofthesolidandatthe

sametimeareusedasacriteriaidentifyingaclassofmaterialsknownas

semiconductorsareconsidered./kra??t?ri?/標(biāo)準(zhǔn)1

SemiconductorProperties

1.1ElectricalConductivityofSolids/??tɑ?m?k

/原子的3Text

Electricalconductivityσ,whichisaninverseofresistivityρ(ρ=1/σ)and

whichisdeterminedbytheatomicstructureofmaterials,representsability

ofmaterialtoconductelectricity.

Electronsareplayingaroleofelectriccharge

carriersinthesolid.Themainfactorcontrollingelectricalconductivityσofthesolidisanumberofelectronswhich

arefree./??tɑ?m?k/原子的1

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity/?k?ri?rz/載流子4(a)

Schematicdepictionofanatomusing

siliconwith4electronsinthe

outermostshellMasanexample.

/?ve?l?ns??lektrɑ?n/價(jià)電子/s??f??(?)nt/足夠的/?ba?nd??/束縛的1

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity

(b)valenceelectronacquiresenergysufficientto

overcomebindingenergyandtobecomeafreeconductionelectron.5(a)

separated.

1

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity

(b)broughttogetherandformingcovalent

bonds.

Siliconatoms

(c)electronreleasedfromthecovalentbondleavingbehindpositivelycharge

holewhichisfreetomoveandtocarrypositivecharge./?ko??ve?l?ntbɑ?nz/共價(jià)鍵61

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity

Figure

(a)

showstwoseparatedfromeachothersiliconatomsschematicallyrepresentedbypositivelychargedatom

coresand

fourvalenceelectronsassociatedwiththeouter-mostatomicshell.When

broughttoclosecontactatomswillformabondusingtwovalenceelectrons,

onefromeachatomparticipatinginthebond(Fig

(b)).Abondcreated

thiswayisreferredtoasacovalentbond.Toformcovalentlybondedlattice

allfourvalenceelectronsofanatomareusedtoformbondswithfourneighboringatomsleavingnofreeelectrons.Ameasurableenergyisrequiredto

breakacovalentbondandtoreleaseanelectronmakingitavailableforconduction(Fig

(c)).Materialsfeaturingcovalentbondsarenotexpected

tobegoodconductorsofelectricityandassucharecommonlyreferredto

assemiconductors./?ve?l?ns??lektrɑ?nz/價(jià)電子71

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity

Theresultoftheelectronbeingreleasedfromthecovalentbond(Fig

(c))isaleftbehind“hole”whichfeaturesthesameaselectron,

butpositiveelectriccharge.Similarlytotheelectron,theholecanmovein

semiconductorinthepresenceofelectricfield,andthus,canactasacarrier

ofthepositiveelectriccharge.

Siliconatoms電場(chǎng)81

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.2

Energybandstructureandelectricalconductivity

electricalconductivityofsolidsofinterestisthe

outermostsectionoftheenergybandstructureconsistingofvalencebands

andconductionbandsseparatedbytheenergygapasshowninFig

(a).

Theenergydifferencebetweenedgesoftheconduction(Ec)andvalence

(Ev)bandsisameasureoftheenergygapwidthEgalsoreferredtoasa

bandgapwidth.EnergybandText/k?n?d?k?nb?nd/導(dǎo)帶帶隙91

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.2

Energybandstructureandelectricalconductivity

Letusconsidernowsolidswhichfeaturevalencebandscompletelyfilled

withelectrons(Fig

(a)).Here,thevalenceelectronshavetoovercomethe

energygapinordertobecomeconductionelectrons.Otherwise,considering

completelyoccupiedvalencebands,no“tiedup”valenceelectroncancarry

electricalcurrent.Inconsequence,theenergyinexcessofEg,orinother

wordshighenoughtobreakinteratomicbondsandreleasevalenceelectrons,

hastobesuppliedtothesolidtomakeitelectricallyconductive.Following

thisreasoningthevalueofEgcanbeusedasameasuredefiningabilityof

varioussolidstocarryelectriccurrent.Dependingonthesolid,theenergygapwidthmayvaryfrom0eVformetals(Fig(b))toashighas10eVforinsulatorswhereelectronvolt(eV)isaunitofenergyuniversallyadoptedinsemiconductorterminology./?t??rm??nɑ?l?d?i/術(shù)語(yǔ)/??nt?r??tɑ?m?k/原子間的價(jià)帶101

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.2

EnergybandstructureandelectricalconductivitySolidsfeaturingnarrowerenergygap(Eg<~5eV),andknownassemiconductors,allowmanipulationoftheirelectricalconductivityoverseveralordersofmagnitudeandareconductiveatroomtemperature.【Intrinsicsemiconductor】

Inthecaseofperfectlychemicallypureanddefect-freesemiconductor,referredtoasintrinsicsemiconductor,theFermilevelispositionedinthemiddleoftheenergygap./m??n?pju?le??n/操縱/?di?fekt/缺陷/p??z??nd/放置于11Introduction

Toallowelectricalconductivity,freetomovearoundcarriersofanelectric

chargemustbeavailableinthebodyofthesolid.Concentrationofcharge

carriers(numberofcarrierspercm3),thewaytheyaregenerated,andthe

mechanismoftheirtransportacrossthesolidplaythekeyroleindefining

electricalconductivityofanysemiconductormaterial./?mek?n?z?m/機(jī)制1

SemiconductorProperties半導(dǎo)體特性

1.2ElectricChargeCarriers載流子12TextTherearetwotypesofelectricchargecarriersinsemiconductors:electronscarryingelementarynegativechargeq

(q=1.602×10?19

coulombs),andholeswhichcarrythesamecharge,but

positive.Semiconductorsinwhichconcentrationofelectronsnexceedsconcentrationofholesp(n>>p)arereferredtoasn-type

semiconductors.Inthesamewaysemiconductorsinwhichconcentrationof

holespexceedsconcentrationofelectrons(p>>n)arereferredtoasp-type

semiconductors./?ku?lo?m/庫(kù)侖1

SemiconductorProperties半導(dǎo)體特性

1.2ElectricalConductivityofSolids固體的導(dǎo)電性1.2.1

Electronsandholesascarriersofelectriccharge電子與空穴

13

Tomakeanygivensemiconductorn-typeorp-type,properlyselectedalienelementsneedtobeaddedtothehost

semiconductor.Theprocessisknownasdopingandalienelementsadded

arereferredtoasdopants(sometimestermimpuritiesisusedinstead).Infact,onedopantatompermillionhostatomsisenoughto

observenoticeablechangesinsemiconductor’sconductivitytypen,orp.1

SemiconductorProperties半導(dǎo)體特性

1.2ElectricalConductivityofSolids固體的導(dǎo)電性1.2.1

Electronsandholesascarriersofelectriccharge電子與空穴

【Controlofconductivitybydoping】/ho?st/宿主141

SemiconductorProperties半導(dǎo)體特性

1.2ElectricalConductivityofSolids固體的導(dǎo)電性1.2.1

Electronsandholesascarriersofelectriccharge電子與空穴

【Controlofconductivitybydoping】Illustrationof(a)n-typedoping(donors),(b)p-typedoping(acceptors).15

Selectionofdopantatomsisbasedonthenumberofvalanceelectrons

featuredbythehostatoms.Ifforexamplethehostatomsfeaturefour

valanceelectrons,thentheelementswithfivevalanceelectrons

needstobeintroducedintothelatticetoaddfreeelectronsandmakehost

materialn-type.Dopantatomsarereferredtoasdonorsinthiscaseand

theirconcentrationisdenotedasND.Inthecourseofthedopingprocessa

dopantatomsubstitutesforthehostatominthelatticethenusesitsfour

electronstoformcovalentbondwithadjacenthostatomsleavingonefreeelectronreadytoactasachargecarrier(Fig(a)).Undertheequilibriumconditionconcentrationofelectronsinn-typesemiconductorn=ND>>p

andelectronsareactingasmajoritycarriers.1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.1

Electronsandholesascarriersofelectriccharge/?i?kw??l?bri?m/平衡/??d?e?s(?)nt/鄰近的/m??d???r?ti/大多數(shù)/?l?t?s/晶格16

Inordertomakehostmaterialp-typeratherthann-type,dopantatoms

featuringthreevalanceelectronsareused.Inthiscase,inordertoform

acovalentbondwithadjacentatomsinthelatticedopantatomneedsto

acceptanelectronfromtheexistingbondsleavingbehindaholewhichis

freetomovearoundandtocontributetoelectricalconductivityofthehost

materialandmakingitp-type(Fig

(b)).1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.1

Electronsandholesascarriersofelectricchargep-typedoping(acceptors)17Text1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.2

Generationandrecombinationprocesses(a)Generationoftheelectron-holepairasaresultofband-to-bandgeneration.

(b)annihilationoftheelectron-holepairasaresultofband-to-band

recombination./??na???le??(?)n/湮沒(méi)18

Generationandrecombinationprocessesarecontrollingtheavailabilityof

freechargecarriersinsemiconductors.Generationistheprocessoffree

chargecarriersformationinsemiconductorsresultingfromtheelectronacquiringenergyfromoutsideoftheatom,forinstancethermalenergyor

energyoflight.Theenergysuppliedtosemiconductorneedstobesufficient

toovercomeenergygapandtoallowelectron’stransitionfromthevalence

bandwhereitcannotmove,totheconductionbandwhereitcanmove,

andthus,contributetotheelectricalconductivityofthesolid.Anoutcome

oftheprocessisanemptystateleftinthevalancebandknownasahole

(Fig

(a)).1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.2

Generationandrecombinationprocesses結(jié)果19

Theprocessofrecombinationisoppositetogenerationandresultsinthe

annihilationoftheelectron-holepairbyelectronsreleasingenergyequivalent

totheenergygapEgandtransitioningfromtheconductiontothevalance

bandwheretheyrecombinewithholes.1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.2

Generationandrecombinationprocessesrecombinationprocess/??na???le??(?)n/湮沒(méi)20Text1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.3

Chargecarriersinmotion【Chargecarriertransport】Therearetwo

mechanismsthatcangenerateelectriccurrentresultingfromthenetflowof

electronsand/orholesinsemiconductor.

Firstisadrift(driftcurrent)whichisamovementofchargecarriers

drivenbytheelectricfieldE.

Secondmechanism,whichdoesnotrequireelectricfieldandwhichis

specifictosemiconductors,isadiffusion(diffusioncurrent).Inthiscasethe

flowofcarriersisdrivenbyconcentrationgradient,orinotherwords,by

non-uniformdistributionofchargecarriersinsemiconductor.凈流不統(tǒng)一21Introduction

Incontrasttoothersolids,certainkeyphysicalcharacteristicsofsemiconductorsarealteredwhensemiconductorisexposedtoexternallyappliedelectric

and/ormagneticfield,aswellastolightortemperature./m?ɡ?net?k/磁場(chǎng)1

SemiconductorProperties

1.3SemiconductorsandExternalInfluences22Text1

SemiconductorProperties

1.3SemiconductorsandExternalInfluences1.3.1

Semiconductorandelectricandmagneticfields【Chargecarriertransport】

Controlofelectricalconductionofsemiconductorinthelimitedregions,typicallynearitssurfacecanbeaccomplishedviathefield-effect.(a)electronsdriftcurrentin

n-typesemiconductorsampleis(b)alteredbythenegativepotentialappliedtothe

surfaceofthesample.Schematicillustrationofthefield-effect負(fù)電勢(shì)23Text1

SemiconductorProperties

1.3SemiconductorsandExternalInfluences1.3.2

Semiconductorsandlight【Conversionoflightintoelectriccurrent】【Conversionoflightintoelectriccurrent】

ThelightilluminatingsemiconductormaterialcarriesenergyEwhichis

absorbedinsemiconductorwhenE>Eg,i.e.whenenergyoflightislarger

thantheenergygapofsemiconductor.

Acurrentflownintosemiconductorasaresultofappliedvoltagewillbringalonganincreased

concentrationoffreechargecarriers.24Text1

SemiconductorProperties

1.3SemiconductorsandExternalInfluences1.3.3

SemiconductorsandtemperatureSchematicqualitativerepresentationofthechangesofelectronconcentrationnand

conductivityσofn-typesemiconductorwithtemperature.

Asitshouldtranspirefromtheaboveconsiderations,

temperatureplaysan

importantroleinessentiallyallfacetsofphysicalcharacteristicsofsemiconductors./tr?n?spa??r/發(fā)生/?kwɑ?l?te?t?v/定性的25IntroductionReductionofthe

sizeofsemiconductormaterialtotheatomicscaledimensions,bringsabout

permanentchangesinitsphysicalpropertiesdrasticallyaffectingcharge

transportmechanismandlightabsorptionandemissioncharacteristics.1

SemiconductorProperties

1.4SemiconductorsinNanoscale/?b?z??rp?n/吸收/i?m??n/發(fā)射261

SemiconductorProperties

1.4SemiconductorsinNanoscale

Physicalpropertiesofsemiconductorarechangingasmaterialgeometry

ischangedfrom(a)not

geometricallyconfinedthree-dimensional,3D,sampleto

(b)2Dmaterialsystem,(c)1Dmaterialsystem,and(d)0Dmaterialsystem./d?i?ɑ?m?tri/幾何1

SemiconductorProperties

1半導(dǎo)體特性27In-classexercisConnecttheEnglishwords/phrasesandChinesemeaningwithlines.acceptorsfield-effectelectrondopingbandgaprecombinationresistivitycarriersmobilityvalence

band摻雜帶隙電阻率遷移率載流子電子受主復(fù)合價(jià)帶場(chǎng)效應(yīng)1

SemiconductorProperties

1半導(dǎo)體特性28In-classexercisFillintheblankswithproperwordsorphrases.1.Semiconductorsinwhichconcentrationofelectronsnexceedsconcentrationofholesp

arereferredtoas

semiconductors.2.Inordertomakehostmaterialp-typeratherthann-type,dopantatoms

featuring

valanceelectronsareused.3.Therearetwo

mechanismsthatcangenerateelectriccurrentresultingfromthenetflowof

electronsand/orholesinsemiconductor.

Firstisadrift,secondisa

.

1

SemiconductorProperties

1半導(dǎo)體特性29KeyTerms單詞/短語(yǔ)音標(biāo)中文含義acceptors/?k?sept?r/受主electron-hole

pair/??lektrɑ?n-ho?l/電子-空穴對(duì)bandgap/b?nd?ɡ?p/帶隙electron/??lektrɑ?n/電子bandgap

engineering/b?nd?ɡ?p?end???n?r??/帶隙工程energy

gap/?en?d?iɡ?p/能隙carrier

lifetime/?k?ri?r?la?fta?m/載流子壽命energy

gap

width/?en?d?iɡ?p

w?dθ/能隙寬度conductionband/k?n?d?k?nb?nd/導(dǎo)帶1

SemiconductorProperties

1半導(dǎo)體特性30單詞/短語(yǔ)音標(biāo)中文含義extrinsicsemiconductors/?ks?tr?nz?k?semik?nd?kt?rz/非本征半導(dǎo)體conductionelectrons/k?n?d?k?n??lektrɑnz/導(dǎo)電電子Fermi

level/?f?rmi?levl/費(fèi)米能級(jí)conductivityσ/?kɑ?nd?k?t?