《半导体简介》PPT课件

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1、TechnicalEnglish2021/9/17IntroductiontoSemiconductorsNewwordsconductor导体insulator绝缘体crystalline晶体的valency化合价bond结合covalent共价的DNA脱氧核糖核酸deoxyribonucleicacid2molecule分子solder焊料,焊接polymorphicform多晶型物atom原子intrinsic固有的,本质的doping(半导体)掺杂(质)dopant掺杂物,掺杂剂minuscule极小的hole空穴3本节中用到

2、的几种化学元素（物质）名称：germanium锗silicon硅tin锡boron硼selenium硒arsenic砷tellurium碲antimony锑arsenide砷化物gallium镓4Textpart1Semiconductorsarematerialsthatexhibitpropertiesthatarebetweenametalandanon-metal.Theirelectricalpropertiesarepartwaybetweenaconductorandaninsulator―thustheyarecall

3、ed“semi-conductors”.(Actuallytheyaremuchclosertoinsulatorsthanconductors.)Anumberofmaterialshavetheseproperties:•ThecrystallineformsofmostelementsofGroupIV(valency4)(silicon[1],germanium,tin).5•Someformsofspecificelements—boron(GroupIII),arsenicandantimony(GroupV),selen

4、iumandtellurium(GroupVI).•CrystallinealloysofelementsinGroupIII(valency3)withelementsofgroupV(valency5).Galliumarsenide(acompoundoralloyofgalliumandarsenic)isagoodexamplehere.•SomecompoundsofelementsofGroupVIwithelementsofGroupII.6Probablythemostversatileelementsarethos

5、ewithfourelectronsintheiroutershell(GroupIV:carbon,silicon,germanium,tin,lead).Becauseofthefactthattheycanhavefourbondstofourotherelements,covalentcompoundsofendlesscomplexitycanbeformed.(IndeedDNAisasinglecarbon-basedmolecule.)Alloftheseelementscanexistinmultiplephysic

6、alforms.Carboncantakemanyformssuchasgraphite(aformabitlikeaclassicalmetal)whichconductselectricityverywellordiamond(acrystallineform)whichisaninsulator.7Almostanyonewhohaseversolderedanelectricalconnectionknowsthedifferencebetweenagoodsolderedjoint(wherethemetalsolidifi

7、esinapolymorphicform)anda“dryjoint”wherethesoldercrystallizes.[2]Polymorphicsolderisaverygoodelectricalconductor.Solder(analloyofleadandtin)initscrystallineformisasemiconductor!8Infactcarbonisnotclassifiedbychemistsasasemiconductoreventhoughdiamonddoessemiconductatrelat

8、ivelyhightemperatures(wellaboveroomtemperature).Thetechnicalreasonisthatcarbonhasverystrongmolecularbondswhich