资源描述：
《2.英文翻译04592》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、无锡职业技术学院毕业设计说明书（英文翻译）Semiconductors1SemiconductorsFundamentals1.1SemiconductorsMaterialsSolid-statematerialscanbegroupedintothreeclasses—insulators,semiconductorsandconductors.Insulatorssuchasfusedquartzandglasshaveverylowconductivities.Semiconductorshaveconductiviti
2、es,typicallybetweenthoseofinsulatorsandthoseofconductors.Theconductivityofasemiconductorisgenerallysensitivetotemperature,illumination,magneticfield,andminuteamountofimpurityatoms.Thissensitivityinconductivitymakesthesemiconductoroneofmostimportantmaterialsforelectro
3、nicapplication.Thestudyofsemiconductormaterialsbeganintheearlynineteenthcentury.Overtheyearsmanysemiconductorshavebeeninvestigated.Theelementsemiconductors,thosecomposedofsinglespeciesofatoms,suchassilicon(Si)andgermanium(Ge)canbefoundinColumn4.however,numerouscompou
4、ndsemiconductorsarecomposedoftwoormoreelements.Forexample,galliumarsenide(GaAs)isan3-5compoundthatisacombinationofgallium(Ga)fromColumn3andarsenic(As)fromColumn5.Priortotheinventionofthebipolarin1947,semiconductorswereusedonlyastwo-terminaldevices,suchasrectifiersand
5、photodiodes.Intheearly1950s,germaniumwasthemajorsemiconductormaterial.However,germaniumprovedunsuitableinmanyapplicationsbecausegermaniumdevicesexhibitedhighleakagecurrentsatonlymoderatelyelevatedtemperatures.Inaddition,germaniumoxideiswatersolubleandunsuitedfordevic
6、efabrication.Sincetheearly1960ssiliconhasbecomeapracticalsubstituteandhasnowvirtuallysupplantedgermaniumasamaterialforsemiconductorfabrication.Themainreasonswenowusesiliconarethatsilicondevicesexhibitmuchlowerleakagecurrents,andhigh-qualitysilicondioxidecanbegrownthe
7、rmally.Thereisalsoaneconomicconsideration.Siliconintheformofsilicaandsilicatescomprises25%oftheEarth’scrust,andsiliconissecondonlytooxygeninabundance.Atpresent,siliconisoneofthemoststudiedelementsintheperiodictable;andsilicontechnologyisbyfarthemostadvancedamongallse
8、miconductortechnologies.Manyofthecompoundsemiconductorshaveelectricalandopticalpropertiesthatareabsentinsilicon.Theresemiconductors
