毕业设计英文翻译资料.docx

毕业设计英文翻译资料.docx

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毕业设计英文翻译资料

毕业设计英文翻译资料

题目：

超声波测距仪的设计与制作

院（系）：

专业：

计算机通信工程

学生姓名：

张社强

班级：

学号：

指导教师：

刘争红

年月日

Integratedcircuit

Inelectronics,anintegratedcircuit（alsoknownasIC,microcircuit,microchip,siliconchip,orchip）isaminiaturizedelectroniccircuit（consistingmainlyofsemiconductordevices,aswellaspassivecomponents）thathasbeenmanufacturedinthesurfaceofathinsubstrateofsemiconductormaterial.Integratedcircuitsareusedinalmostallelectronicequipmentinusetodayandhaverevolutionizedtheworldofelectronics.

Integratedcircuitsweremadepossiblebyexperimentaldiscoverieswhichshowedthatsemiconductordevicescouldperformthefunctionsofvacuumtubes,andbymid-20th-centurytechnologyadvancementsinsemiconductordevicefabrication.Theintegrationoflargenumbersoftinytransistorsintoasmallchipwasanenormousimprovementoverthemanualassemblyofcircuitsusingelectroniccomponents.Theintegratedcircuit'smassproductioncapability,reliability,andbuilding-blockapproachtocircuitdesignensuredtherapidadoptionofstandardizedICsinplaceofdesignsusingdiscretetransistors.

TherearetwomainadvantagesofICsoverdiscretecircuits:

costandperformance.Costislowbecausethechips,withalltheircomponents,areprintedasaunitbyphotolithographyandnotconstructedonetransistoratatime.Furthermore,muchlessmaterialisusedtoconstructacircuitasapackagedICdiethanasadiscretecircuit.Performanceishighsincethecomponentsswitchquicklyandconsumelittlepower（comparedtotheirdiscretecounterparts）becausethecomponentsaresmallandclosetogether.Asof2006,chipareasrangefromafewsquaremillimeterstoaround350mm2,withupto1milliontransistorspermm2.

Amongthemostadvancedintegratedcircuitsarethemicroprocessorsor"cores",whichcontroleverythingfromcomputerstocellularphonestodigitalmicrowaveovens.DigitalmemorychipsandASICsareexamplesofotherfamiliesofintegratedcircuitsthatareimportanttothemoderninformationsociety.Whilethecostofdesigninganddevelopingacomplexintegratedcircuitisquitehigh,whenspreadacrosstypicallymillionsofproductionunitstheindividualICcostisminimized.TheperformanceofICsishighbecausethesmallsizeallowsshorttraceswhichinturnallowslowpowerlogic（suchasCMOS）tobeusedatfastswitchingspeeds.

ICshaveconsistentlymigratedtosmallerfeaturesizesovertheyears,allowingmorecircuitrytobepackedoneachchip.Thisincreasedcapacityperunitareacanbeusedtodecreasecostand/orincreasefunctionality—seeMoore'slawwhich,initsmoderninterpretation,statesthatthenumberoftransistorsinanintegratedcircuitdoubleseverytwoyears.Ingeneral,asthefeaturesizeshrinks,almosteverythingimproves—thecostperunitandtheswitchingpowerconsumptiongodown,andthespeedgoesup.However,ICswithnanometer-scaledevicesarenotwithouttheirproblems,principalamongwhichisleakagecurrent（seesubthresholdleakageforadiscussionofthis）,althoughtheseproblemsarenotinsurmountableandwilllikelybesolvedoratleastamelioratedbytheintroductionofhigh-kdielectrics.Sincethesespeedandpowerconsumptiongainsareapparenttotheenduser,thereisfiercecompetitionamongthemanufacturerstousefinergeometries.Thisprocess,andtheexpectedprogressoverthenextfewyears,iswelldescribedbytheInternationalTechnologyRoadmapforSemiconductors（ITRS）.

Onlyahalfcenturyaftertheirdevelopmentwasinitiated,integratedcircuitshavebecomeubiquitous.Computers,cellularphones,andotherdigitalappliancesarenowinextricablepartsofthestructureofmodernsocieties.Thatis,moderncomputing,communications,manufacturingandtransportsystems,includingtheInternet,alldependontheexistenceofintegratedcircuits.

Integratedcircuitscanbeclassifiedintoanalog,digitalandmixedsignal（bothanaloganddigitalonthesamechip）.

Digitalintegratedcircuitscancontainanythingfromonetomillionsoflogicgates,flip-flops,multiplexers,andothercircuitsinafewsquaremillimeters.Thesmallsizeofthesecircuitsallowshighspeed,lowpowerdissipation,

andreducedmanufacturingcostcomparedwithboard-levelintegration.ThesedigitalICs,typicallymicroprocessors,DSPs,andmicrocontrollersworkusingbinarymathematicstoprocess"one"and"zero"signals.

AnalogICs,suchassensors,powermanagementcircuits,andoperationalamplifiers,workbyprocessingcontinuoussignals.Theyperformfunctionslikeamplification,activefiltering,demodulation,mixing,etc.ICscanalsocombineanaloganddigitalcircuitsonasinglechiptocreatefunctionssuchasA/DconvertersandD/Aconverters.Suchcircuitsoffersmallersizeandlowercost,butmustcarefullyaccountforsignalinterference.

ThesemiconductorsoftheperiodictableofthechemicalelementswereidentifiedasthemostlikelymaterialsforasolidstatevacuumtubebyresearcherslikeWilliamShockleyatBellLaboratoriesstartinginthe1930s.Startingwithcopperoxide,proceedingtogermanium,thensilicon,thematerialsweresystematicallystudiedinthe1940sand1950s.Today,siliconmonocrystalsarethemainsubstrateusedforintegratedcircuits（ICs）althoughsomeIII-VcompoundsoftheperiodictablesuchasgalliumarsenideareusedforspecializedapplicationslikeLEDs,lasers,solarcellsandthehighest-speedintegratedcircuits.Ittookdecadestoperfectmethodsofcreatingcrystalswithoutdefectsinthecrystallinestructureofthesemiconductingmaterial.

SemiconductorICsarefabricatedinalayerprocesswhichincludesthesekeyprocesssteps:

Imaging

Deposition

Etching

Themainprocessstepsaresupplementedbydopingandcleaning.

Integratedcircuitsarecomposedofmanyoverlappinglayers,eachdefinedbyphotolithography,andnormallyshownindifferentcolors.Somelayersmarkwherevariousdopantsarediffusedintothesubstrate（calleddiffusionlayers）,somedefinewhereadditionalionsareimplanted（implantlayers）,somedefinetheconductors（polysiliconormetallayers）,andsomedefinetheconnectionsbetweentheconductinglayers（viaorcontactlayers）.Allcomponentsareconstructedfromaspecificcombinationoftheselayers.

Inaself-alignedCMOSprocess,atransistorisformedwhereverthegatelayer（polysiliconormetal）crossesadiffusionlayer.

SinceaCMOSdeviceonlydrawscurrentonthetransitionbetweenlogicstates,CMOSdevicesconsumemuchlesscurrentthanbipolardevices.

Arandomaccessmemoryisthemostregulartypeofintegratedcircuit;thehighestdensitydevicesarethusmemories;butevenamicroprocessorwillhavememoryonthechip.Althoughthestructuresareintricate–withwidthswhichhavebeenshrinkingfordecades–thelayersremainmuchthinnerthanthedevicewidths.Thelayersofmaterialarefabricatedmuchlikeaphotographicprocess,althoughlightwavesinthevisiblespectrumcannotbeusedto"expose"alayerofmaterial,astheywouldbetoolargeforthefeatures.Thusphotonsofhigherfrequencies（typicallyultraviolet）areusedtocreatethepatternsforeachlayer.Becauseeachfeatureissosmall,electronmicroscopesareessentialtoolsforaprocessengineerwhomightbedebuggingafabricationprocess.

Theearliestintegratedcircuitswerepackagedinceramicflatpacks,whichcontinuedtobeusedbythemilitaryfortheirreliabilityandsmallsizeformanyyears.Commercialcircuitpackagingquicklymovedtothedualin-linepackage（DIP）,firstinceramicandlaterinplastic.Inthe1980spincountsofVLSIcircuitsexceededthepracticallimitforDIPpackaging,leadingtopingridarray（PGA）andleadlesschipcarrier（LCC）packages.Surfacemountpackagingappearedintheearly1980sandbecamepopularinthelate1980s,usingfinerleadpitchwithleadsformedaseithergull-wingorJ-lead,asexemplifiedbysmall-outlineintegratedcircuit--acarrierwhichoccupiesanareaabout30–50%lessthananequivalentDIP,withatypicalthicknessthatis70%less.Thispackagehas"gullwing"leadsprotrudingfromthetwolongsidesandaleadspacingof0.050inches.

Inthelate1990s,PQFPandTSOPpackagesbecamethemostcommonforhighpincountdevices,thoughPGApackagesarestilloftenusedforhigh-endmicroprocessors.IntelandAMDarecurrentlytransitioningfromPGApackagesonhigh-endmicroprocessorstolandgridarray（LGA）packages.

Ballgridarray（BGA）packageshaveexistedsincethe1970s.Flip-chipBallGridArraypackages,whichallowformuchhigherpincountthanotherpackagetypes,weredevelopedinthe1990s.

Mostintegratedcircuitslargeenoughtoincludeidentifyinginformationincludefourcommonsections:

themanufacturer'snameorlogo,thepartnumber,apartproductionbatchnumberand/orserialnumber,andafour-digitcodethatidentifieswhenthechipwasmanufactured.Extremelysmallsurfacemounttechnologypartsoftenbearonlyanumberusedinamanufacturer'slookuptabletofindthechipcharacteristics.

Themanufacturingdateiscommonlyrepresentedasatwo-digityearfollowedbyatwo-digitweekcode,suchthatapartbearingthecode8341wasmanufacturedinweek41of1983,orapproximatelyinOctober1983.

StructureandfunctionoftheMCS-51series

StructureandfunctionoftheMCS-51seriesone-chipcomputerisanameofapieceofone-chipcomputerserieswhichIntelCompanyproduces.Thiscompanyintroduced8top-gradeone-chipcomputersofMCS-51seriesin1980afterintroducing8one-chipcomputersofMCS-48seriesin1976.Itbelongtoalotofkindsthislineofone-chipcomputerthechipshave,suchas8051,8031,8751,80C51BH,80C31BH,etc