電子信息專業(yè)英語（第二版）課件：Microelectronics

MicroelectronicsPassageAIntroductiontoMicroelectronics

PassageBTheSimpleAtom,Conductors,InsulatorsandSemiconductors

PassageCDiodeandTransistor

PassageAIntroductiontoMicroelectronics

Theexploringofspaceandthedevelopmentofearthsatelliteshasincreasedtheimportanceofreducingthesizeandweightofelectroniccircuits.Also,eventhoughelectricityflowsquiterapidlyincomputersthetimedelayofthesignalintheinterconnectionsbetweenelectroniccomponentsisanimportantconsideration.Iftheinterconnectionsarereducedinsize,acomputercanperformoperationsatafasterspeed.

Microelectronicsinvolvestheminiaturizationofregularelectroniccircuits.Acompleteelectroniccircuit,anoperationalamplifierforexample,whichcontainslargenumbersofindividualinterconnectedcomponents,suchasdiodesresistors,transistors,etc.maybeformedonaverysmallsinglesubstrate.Thecompleteminiaturizedcircuitisthencalledanintegratedcircuit.

Integratedcircuitsaresmall,light,rugged,andreliable.Theyrequirelesspowerandlowervoltagesthanequivalentmacroscopiccircuits;consequentlytheyoperateatlowertemperatures,andindividualcomponentsmaybeclosetogetherwithoutexceedingtheoperatingtemperaturelimit.RelativelylittlestraycapacitanceandshorttimedelaysareproducedbecauseoftheshortinterconnectionsbetweentheindividualcomponentsinIC.MaintenanceissimplifiedbecauseifacomponentoftheICfailsthecompleteICisusuallyreplaced.MassproductiontechniquesofplanetechnologyhavereducedthecostofmanyICsothattheyarealmostasinexpensiveasasingletransistor.EventuallymostconventionalcircuitswillbereplacedbyIC.

Therearetwotypesofbasicintegratedcircuit:monolithicintegratedcircuitandthethinorthickfilm.MonolithicICareconstructedinasinglesubstrateofsinglecrystalsemiconductor,usuallysilicon.ThinorthickfilmsICareformedonthesurfaceofaninsulatingmaterialsuchasglassoraceramic.HybridICcontainsmorethanasinglesubstrate,thetermhybridisalsoappliedtocombinationsofmonolithicandthinorthickfilmIC.

Integratedcircuitsarealsoclassifiedaccordingtotheirfunctions.DigitalorlogicalICareusedasswitches,theyareeitheronoroff.Incomputerstheonandoffstatescorrespondto0or1.OtherICiscalledlinearoranalogIC.[1]Integratedcircuitscanbeproducedusingeitherbipolaroruniquepolartransistors.Fieldeffecttransistors(FET)haveaadvantagesoverbipolartransistorsinmanycaseshowever.Theyarerelativelyhigh-impedancedevices,withacorrespondingreductionincurrentandpowerdissipation,andyethavehighpowergain.Thereductioninpowerdissipationisparticularlyimportantwhereacomplexcircuitistobeconcentratedintoasmallspace.Theproblemofextractingtheheatgeneratedinthecircuitmaythenbeadifficultone.[2]TheformofconstructionoftheFET,andparticularlytheMOSFET,alsolendsitselfwelltointegratedcircuitfabrication,andenablesresistorsandcapacitorstobeincludedreadilyintheintegratedcircuit.

Mostelectroniccircuitsarecomposedofactivedevices,e.g.transistorsanddiodes,togetherwithresistors(forbias,collectorload,impedancetransformation,etc.)andcapacitors(e.g.forcouplingacsignalswhileblockingdcsupplies).Eachoftheseelementscanbeproducedinaformsuitableforintegratedcircuitinclusionwithinlimitations,e.g.capacitancevaluesmustnotbetoolarge.Someelementsaredifficulttoproduceinasuitableform,e.g.inductiveelements,orlargecapacitors.Usuallysomealternativecircuitformcanbedevisedthatdispenseswiththerequirement.Otherwisetheymustbeincludedasanexternallumpedelement.Notes

［1］Intergradedcircuitsarealsoclassifiedaccordingtotheirfunctions.DigitalorlogicalICareusedasswitches,theyareeitheronoroff.Incomputerstheonandoffstatescorrespondto0or1.OtherICiscalledlinearoranalogIC.

也可根據(jù)其功能不同對集成電路進(jìn)行分類。數(shù)字IC(也稱為邏輯IC)通常用作開關(guān),表示接通或關(guān)斷。在計(jì)算機(jī)中,接通和關(guān)斷狀態(tài)分別對應(yīng)“0”或“1”。另一種IC被稱為線性或模擬IC。

·either...or...表示兩者擇一,在文中譯為“要么……要么……”。［2］Thereductioninpowerdissipationisparticularlyimportantwhereacomplex

circuitistobeconcentratedintoasmallspace.Theproblemofextractingtheheatgeneratedinthecircuitmaythenbeadifficultone.

減小功率損耗是非常重要的,其方法是將一個(gè)復(fù)雜的電子線路集成為一小塊。這使得釋放電路工作時(shí)產(chǎn)生的熱量變成一個(gè)難題。

·Theproblemof...maythenbeadifficultone.文中的one表示強(qiáng)調(diào)這個(gè)問題,這種句式在科技英語中常被使用。

·extractingtheheat為釋放熱量的意思,extract的本意為“抽出,剝離”。在電子線路中,器件工作均會(huì)產(chǎn)生熱量,如果不能及時(shí)散熱,器件就不能穩(wěn)定工作。Exercises

1.PleasetranslatethefollowingsentencesintoEnglish,usinginfiniteverbonthepartsunderlined.

(1)為了測量電阻,我們使用單位“歐姆”。

(2)重要的是要應(yīng)用這些定律。

(3)這種裝置能用來測量電流、電壓、電阻。

(4)我們想要求這個(gè)電路中的電流。

(5)無線電波的用途之一是發(fā)送信息。

(6)在這種情況下該物體被說成帶電了。

(7)我們感到理解這個(gè)概念很困難。

2.PleasetranslatethefollowingsentencesintoChinese.

(1)Itisassumedthatthereaderhasageneralknowledgeofcircuittheory.

(2)Whichofthesemethodsisdetermine

Reqdependsuponwhichistheeasiestinanygivensituation.

(3)Itisanexperimentalfactthatanelectricfieldisestablishedinaconductingrodwhenthereisatemperaturedifferencebetweenitsends.

(4)Thatthisconditionissufficientisobvious.

(5)Itcanbeshownthatanyrationalfunctionofsin

x

andcos

x

canbeintegrated.

(6)Amajoradvantageofthisdeviceisthatitoperatescontinuously.

(7)Inthischapterweshalldeterminewhichloadreceivesthemaximumpowerforagivenpracticalvoltagesource.

PassageBTheSimpleAtom,Conductors,InsulatorsandSemiconductors

TheSimpleAtom

Thematerialsthatmakeupouruniversearecomposedofoveronehundredbasicandindividualtypesofmattercalledelements.Ninety-twooftheseelementsoccurnaturallyandtheremaindersareman-made.Eachelementhasaseparateidentifyofitsown,thatis,notwoelementshavethesamephysicalandchemicalproperties,norcananelementbesubdividedbyordinaryphysicalandchemicalmeansintosimpleelements.[1]Examplesofelementsaregold,mercuryandoxygen.

Elementscontainsmallerparticlescalledatoms.Inanyoneelementtheatomsareidenticalinstructure.Thedifferencebetweenanytwoelementssuchasgoldandmercuryisintheiratomicstructures.Theyhaveincommon,however,arelativelyheavyinnercorecalledanucleussurroundedbyoneormoreextremelylightparticlesofmattercalledelectrons.Thesimplestnucleusisamassofmatterabout2,000timestheweightofanelectron,andiscalledaproton.Morecomplexnucleicontainvariouscombinationsofprotonsandneutrons.Aneutronisaprotoncombinedwithanelectronandiselectronicallyneutral.

Electronswhirlaroundnucleiinmuchthesamemannerthattheplanetsofoursolarsystemtravelaroundthesun.Thedifferencebetweenanatomofoneelementandthatofanotherisinthenumberofprotonsandneutronscontainedinthenucleus.[2]Alltheelementsintheuniverse,andthereforeallmatter,iscomposedofprotons,neutrons,andelectrons.

Theremustbeforceofattractionbetweenanucleusandtheelectronssurroundingit,otherwisetheelectronswouldflyoffintospace,inordertounderstanditsnature,wefindithelpfultocallthisforceacharge.Thechargeofthenucleusisdefinedaspositive,andtheoppositechargeoftheelectron,negative.Inviewofthefactthatoppositesattract,theforcebetweenthenucleusandtherotatingelectronarounditpreventstheelectronfromflyingoffintospace.

Anatom,whichhasallofitsorbital(rotating)electronshasasmanypositivechargesandthereforethenetchargeiszero.Whenanatomlosesanelectronthebalanceofchargeisdisturbedandtheatombecomespositivelycharged.Inthiscondition,theatomiscalledapositiveion.Incomparison,whenanatomacquiresanelectron,thebalanceofchargesisagaindisturbedandtheatombecomesnegativelycharged,suchanatomisreferredtoasanegativeion.

Conductors,InsulatorsandSemiconductors

Anysubstance,whichallowselectronstoflowfreelythroughitsstructureiscalledaconductor.Ingeneral,metalsaregoodconductors.Adefiniterelationshipexistsbetweengoodconductorsandtheiratomicstructures.Ingoodconductors,theouter-ringelectrons,whicharealsocalledvalenceelectrons,maybereleasedfromtheirorbitswithrelativeease.Atomwith1,2and3outerringelectrons,andthereforemostmetalsaregoodconductors.

Substance,whichpreventthepassageofelectronsthroughtheirstructuresarecalledinsulators.Insulatorshaveveryfeweasilyremovedelectronsintheirouterrings.Therearenoperfectinsulators:first,becauseofthepresenceofimpurities(foreignmaterials)whichcanneverbeentirelyremoved;andsecond,becauseevenasmallamountofheatwillcauseacertainnumberofvalenceelectronstobefreedfromtheiratoms.

Insulatorsgenerallyhaveverystableatomicstructures,ofwhichthe4-electronouter-ringstructureistypical.Insuchastructure,thereisanabsenceofeasilyremovedelectrons.Exampleofgoodinsulatorsarecertaincompoundsofcarbon(abasicingredientofrubber)anddiamond,whichhasasimilaratomicstructure.

Semiconductorsareagroupofmaterials,whichconductelectronspoorlyandthereforecannotproperlybeclassifiedeitherasconductorsorinsulators.Generally,semiconductorsdifferfrominsulatorsinthattheirouter-ringelectronscandetachthemselvesfromtheirorbitsmoreeasilythanininsulators.Typicalsemiconductorsmaterialsaregermaniumandsilicon.

Impuritiesmaybeaddedtopuresemiconductors.Thisresultsinsemiconductormaterials,whichmayeitherhaveanexcessoffreeelectronsoradeficiencyoforbitalelectrons.WhenanexcessofelectronsispresentwecallthematerialN-type;whenlackoforbitalelectronsoccurs,wecallthematerialP-type.BothN-typeandP-typesemiconductorsaremadebytreatedmaterials.suchasgermaniumandsiliconwithimpuritiessuchasarsenicandindium.Theadditionofimpuritiestosemiconductorsiscalleddoping.

Notes

［1］Eachelementhasaseparateidentityofitsown,thatis,notwoelementshavethesamephysicalandchemicalproperties,norcananelementbesubdividedbyordinaryphysical

andchemicalmeansintosimpleelements.

每一種元素均有它自己的標(biāo)識(shí),也就是說,沒有兩個(gè)元素具有相同的物理和化學(xué)特性,一種元素也不能以普通的物理或化學(xué)方法被分為兩種簡單的元素。

·thatis是插入語。

·nor也不,提到句首使用時(shí),句子要倒裝,表示強(qiáng)調(diào)。［2］Eletronswhirlaroundnucleiinmuchthesamemannerthattheplanetsofour

solarsystemtravelaroundthesun.Thedifferencebetweenanatomofoneelementandthatofanotherisinthenumberofprotonsandneutronscontainedinthenucleus.

電子圍繞原子核旋轉(zhuǎn),其方式類似于太陽系中行星圍繞太陽旋轉(zhuǎn)。一種元素的原子和另一種元素的原子的差別在于其原子核中的質(zhì)子數(shù)和中子數(shù)。

·inmuchthesamemannerthat中,in...manner意為“以……的方式”,that是manner的定語從句。［3］BothN-typeandP-typesemiconductorsaremadebytreatedmaterials,suchasgermaniumandsiliconwithimpuritiessuchasarsenicandindium.

N型半導(dǎo)體和P型半導(dǎo)體是利用雜質(zhì)摻入純凈半導(dǎo)體而形成的,如將雜質(zhì)砷和銦摻入鍺和硅中。

·aremadebytreatedmaterial,treat原意為對峙,treatedmaterials指前文將雜質(zhì)摻入純凈半導(dǎo)體的過程。Exercises

1.True/False.

(1)Thematerialsthatmakeupouruniverseareatoms.()

(2)Generallywedistinguishtheelementsbytheiratomicstructures.Eachatomhasauniqueidentify.()

(3)Theatomisalwayscomposedofproton,neutronsandelectrons.()

(4)Whenthetemperatureishigh,anelectroncanattractamountheatandthenflyoffintospace.()

(5)Thesemiconductorcanpermitthecurrentthroughtheirbodyifsomeconditionissupplied.()

6.??Ifyouputimpuritiesaddingtopuresemiconductors,thisresultsinsemiconductor?materials,whichonlyhaveanexcessoffreeelectrons.()

7.Whenanexcessofelectronsispresent,wecallthematerialP-type;whenlackoforbitalelectronsoccurs,wecallthematerialN-type.()

8.BothN-typeandP-typesemiconductorsaremadebytreatedmaterials.suchasgermaniumandsiliconwithimpuritiessuchasarsenicandindium.()

9.?Thecourseofadditionofimpuritiestosemiconductorsiscalleddoping.()

2.TranslatethefollowingsentencesintoEnglish.

(1)工科學(xué)生應(yīng)該知道如何使用計(jì)算機(jī)。

(2)物體做功的能力被稱為能量。

(3)重要的是我們要把理論應(yīng)用于實(shí)踐。

(4)計(jì)算在這個(gè)電路中流動(dòng)的電流密度是可能的。

(5)這些是常用的設(shè)備。

(6)電壓等取決于電路中的電阻以及所加的電壓。

3.TranslatethefollowingsentencesintoChinese.

(1)Thesecapacitorsarecommonlyusedwherechangeincapacitanceisnecessary.

(2)Theadventofelectronicsisreckonedfromthediscoverythatthecurrentina

vacuumdiodecanbecontrolledbyintroducingathirdelectrode.

(3)Theconceptofworkissoimportantthatitwillbearfurtherdiscussion.

(4)Justasgoodelectricalconductorsarealsogoodconductorsofheat,poorelectricalconductorsarealsopoorthermalconductors.

(5)Bytheuseofelectricalinsulators,electricalcurrentscanbeconfinedtowell-

designedpathsingoodelectricalconductors,whileitisimpossibletoconfineheatcurrentstoacomparableextent.

(6)Thestatementthatamanweighs160poundsisequivalenttoastatementthatheisattractedbytheearthwithaforceof160pounds.

PassageCDiodeandTransistor

TheBasicCrystalJunction(orDiode)

Whenafreeelectronmeetsamovingholeinasemiconductormaterial,theelectronoccupiesthefreespaceandapositiveornegativechargenolongerexists;thatis,thechargeisneutralized.WhenaP-typeandaN-typecrystalarejoinedtomakeasinglesemiconductor,asshowninFigure9.1,currentwillflowinonedirectiononly.Asanexample,whenapowersourceisconnectedtothesemiconductorasshowninFigure9.2,thesemiconductorissaidtobeforwardbiased.Figure4.1ThebasiccrystaljunctionFigure4.2Forwardbiasedconnectionin

Theholeswillberepelledtowardthejunctionbythepositivelychargedbatteryterminal,whereastheelectronsarepushedtowardthejunctionbythebattery’snegativeterminal.

Atthejunction,theelectronscombinewiththehole.ElectronsenterthesemiconductorattheNterminaltoreplacetheelectronsthathavecombinedwiththeholes.Likewise,electronsleavethePterminalbyattractionofpositivevoltageandcreatenewholes.Thismovementofelectrons,fromthenegativevoltagesourcethroughthejunctionandfromthepositiveterminalofsemiconductortopositivevoltagesource,createsacurrentflow.Thuscurrentwillflowinasemiconductorwhenthesemiconductorisforwardbiased.

Whenthepolarityofthepowersourceisreversed,thesemiconductorissaidtobereversebiased.Theholesaremovedawayfromthejunctionbythenegativevoltage,whereastheelectronsaredrawfromthejunctionbythepositivevoltage.Thusthereislittleornocombiningofelectronsandholesatthejunction,andnocurrentwillflow.

Inpracticalterms,therewillalwaysbeafewelectronsandholesnearthejunction,allowingaverysmallcurrenttopass.Thissmallcurrentisknownasleakagecurrentandisusuallyintheorderofafewmicroamperes(orpossiblypicoamperes).

WhenP-typeandN-typeregionsareformedinsamecrystal,thesemiconductorisknownasadiodeorrectifier.Theboundarybetweenthetworegionsistermedajunction.TheP-regionterminaliscalledtheanode,whereastheN-regionterminaliscalledthecathode.

Usually,whensuchsemiconductorsareusedwithsignals,thesemiconductorsarecalleddiodesorsignaldiodes.Whenthedeviceisusedforconversionofalternatingcurrent(ac)todirectcurrent(dc),thesemiconductoriscalledarectifier.

BasicTwo-junctionorBipolarTransistor

Likeadiode,atransistorcanbeusedtoprevent(orlimit)theflowofcurrentinonedirection,Theprimeuseforatransistor,however,istocontroltheamountofcurrentinacircuit.Thisisdonebyaddingasecondjunctiontothebasicdiodejunction,discussedintheabovesection.Forthisreason,suchtransistorsarecalledtwo-junctiontransistorsor,possibly,bipolartransistors.Theauthorpreferstheformertermbutrecognizesthatthelattertermisalsoincommonuse.

Therearetwopossiblearrangementsforthetwo-junctionintransistors:NPN,whereapositivesemiconductormaterial(holes)isplacedbetweentwonegativesemiconductormaterials(electrons),andPNP,wherethenegativematerial(electrons)isplacedbetweentwopositivematerials(holes).

Witheitherjunctionarrangement,thebasictwo-junctiontransistorwillhavethreeelements.Theseelements,showinFigure9.3asanNPNarrangement,aretheemitter,whichemitselectrons;thecollector,whichcollectselectrons;andabase,whichcontrolstheflowofelectronsbycontrollingthechargeconcentrationatthetwo-junctionsoneithersideofthebase.Figure4.3NPNandPNPtwo-junctiontransistorarrangements

Figure9.4showshowtwojunctiontransistoroperatesinitsbasiccircuit.Asshown,theemitter-basejunctionwillpasscurrenteasilybecausethejunctionisforwardbiased.Thecollector-basejunctionwillnotpasscurrent(exceptforasmallleakagecurrent)sincethejunctionisreversebiased.(Thetermbackisoftenusedinplaceofreversebias.)Figure4.4Basictwo-junctiontransistorbiascircuit

ItshouldbenotedthatthepolaritiesofbiasvoltageforanNPNtransistordifferfromthoseofaPNPtransistor;however,thenetresultsarethesame.Forexample,asshowninFigure9.4,theemitterisnegativewithrespecttothebase(NPN)toproduceaforwardbias.InFigure9.4,theemitterispositivewithrespecttobase(PNP)toproducethesameforwardbias.Similarly,thecollectorhasareversebiasforbothNPNandPNP,eventhoughthepolaritiesarerevered.Also,itshouldbenotedthatfornormaloperationanNPNhasitsbasebiasedpositivelywithrespecttoitsemitter.Conversely,aPNPbaseisnegativewithrespecttoitsemitter.

(a)Basictwo-junctiontransistoroperation.Duringnormaloperationofatwo-junctiontransistor,currentwillflowbetweenemitterandbaseandbetweenemitterandcollectorbutnotbetweencollectorandbase.Mostofthecurrentflowsbetweenemitterandcollector,becauseofthelargevoltagedifferenceexistingbetweentheseelements(thesumoftheemitter-basevoltageandthecollector-basevoltage).Thisproducesalargenumberofchargecarriers(positiveholesinaPNPornegativeelectronsinanNPN)thatdiffusethroughthisbaseregionwhenpassingfromemittertocollector(orviceversa).Fewofthesechargecarrierscombinewiththecharge(positiveinNPN,negativePNP)inthebase.

Morechargecarrierswillbepulledoutoftheemitterandmadeavailableforthecollectorifthebase-emittercurrentisincreased.ThiscanbeaccomplishedbymaskingthebasemorenegativeinaPNPtransistororbymakingthebasemorepositiveinanNPNtransistor.

Ifthebase-emittervoltageisdecreased,lesschargecarrierswillbepulledformtheemitterandlessemitter-collectorcurrentwillflow.

Sinceverylittlevoltage(approximately0.2?Vforgermaniumand0.5?Vforsilicon)isrequiredtoproducealargecurrentflowintheemitter,inputpowertoatransistorislow.Mostoftheemittercurrentflowsinthecollectorcircuit,wherethevoltageismademuchlarger.Asaresult,arelativelylargeamountofpowercanbecontrolledinanexternalload(connectedinserieswiththecollectorcircuit)byasmallamountofpowerintheemittercircuit.Thepowergainofatransistor(ther