电子信息专业英语（第二版）课件：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.

也可根据其功能不同对集成电路进行分类。数字IC(也称为逻辑IC)通常用作开关,表示接通或关断。在计算机中,接通和关断状态分别对应“0”或“1”。另一种IC被称为线性或模拟IC。

·either...or...表示两者择一,在文中译为“要么……要么……”。［2］Thereductioninpowerdissipationisparticularlyimportantwhereacomplex

circuitistobeconcentratedintoasmallspace.Theproblemofextractingtheheatgeneratedinthecircuitmaythenbeadifficultone.

减小功率损耗是非常重要的,其方法是将一个复杂的电子线路集成为一小块。这使得释放电路工作时产生的热量变成一个难题。

·Theproblemof...maythenbeadifficultone.文中的one表示强调这个问题,这种句式在科技英语中常被使用。

·extractingtheheat为释放热量的意思,extract的本意为“抽出,剥离”。在电子线路中,器件工作均会产生热量,如果不能及时散热,器件就不能稳定工作。Exercises

1.PleasetranslatethefollowingsentencesintoEnglish,usinginfiniteverbonthepartsunderlined.

(1)为了测量电阻,我们使用单位“欧姆”。

(2)重要的是要应用这些定律。

(3)这种装置能用来测量电流、电压、电阻。

(4)我们想要求这个电路中的电流。

(5)无线电波的用途之一是发送信息。

(6)在这种情况下该物体被说成带电了。

(7)我们感到理解这个概念很困难。

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.

每一种元素均有它自己的标识,也就是说,没有两个元素具有相同的物理和化学特性,一种元素也不能以普通的物理或化学方法被分为两种简单的元素。

·thatis是插入语。

·nor也不,提到句首使用时,句子要倒装,表示强调。［2］Eletronswhirlaroundnucleiinmuchthesamemannerthattheplanetsofour

solarsystemtravelaroundthesun.Thedifferencebetweenanatomofoneelementandthatofanotherisinthenumberofprotonsandneutronscontainedinthenucleus.

电子围绕原子核旋转,其方式类似于太阳系中行星围绕太阳旋转。一种元素的原子和另一种元素的原子的差别在于其原子核中的质子数和中子数。

·inmuchthesamemannerthat中,in...manner意为“以……的方式”,that是manner的定语从句。［3］BothN-typeandP-typesemiconductorsaremadebytreatedmaterials,suchasgermaniumandsiliconwithimpuritiessuchasarsenicandindium.

N型半导体和P型半导体是利用杂质掺入纯净半导体而形成的,如将杂质砷和铟掺入锗和硅中。

·aremadebytreatedmaterial,treat原意为对峙,treatedmaterials指前文将杂质掺入纯净半导体的过程。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)工科学生应该知道如何使用计算机。

(2)物体做功的能力被称为能量。

(3)重要的是我们要把理论应用于实践。

(4)计算在这个电路中流动的电流密度是可能的。

(5)这些是常用的设备。

(6)电压等取决于电路中的电阻以及所加的电压。

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