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1、BasicsemiconductorcrystalstructureTounderstandhowdiodes,transistors,andothersemiconductordevicescandowhattheydo,itisfirstnecessarytounderstandthebasicstructureofallsemiconductordevices.earlysemiconductorswerefabricatedfromtheelementgermanium,butsiliconispreferredinmostmodernapplications.Thecryst
2、alstructureofpuresiliconisofcourse3-dimensional,butthatisdifficulttodisplayortosee,sotheimagetotheleftisoftenusedtorepresentthecrystalstructureofsilicon.foryouphysicstypes,silicon(andgermanium)fallsincolumnⅣaoftheperiodictable.T.hisisthecarbonfamilyofelements.theessentialcharacteristicoftheseele
3、mentsisthateachatomhasfourelectronstosharewithadjacentatomsinformingbonds.Whilethisisanoversimplifieddescription,thenatureofabondbetweentwosiliconatomsissuchthateachatomprovidesoneelectrontosharewiththeother.Thetwoelectronsthussharedareinfactsharedequallybetweenthetwoatoms.Thistypeofsharingiskno
4、wnasacovalentbond.suchabondisverystable,andholdsthetwoatomstogetherverytightly,sothatitrequiresalotofenergytobreakthisbond.了解二極管、晶體管和其他半導體器件可以發(fā)揮他們的功效,首先需要理解所有半導體器件的基本結(jié)構(gòu)。早期的半導體制造從元素鍺開始,但硅在大多數(shù)現(xiàn)代應(yīng)用程序中優(yōu)先使用。當然純硅的晶體結(jié)構(gòu)是三維,但這很難顯示或看到,所以左側(cè)圖像常被用來代表硅的晶體結(jié)構(gòu)。你物理類型、硅和鍺落在列Ⅳa周期性table.T。他是碳元素的家庭。這些元素的基本特點是,每個原子有四個
5、電子與相鄰原子形成分享債券。雖然這是一個過于簡單化的描述,兩個硅原子之間的鍵的性質(zhì),每個原子都提供一個電子來分享。兩個電子從而共享實際上是兩個原子之間的平均分擔。這種類型的共享稱為共價鍵。這種債券是非常穩(wěn)定的,把兩個原子結(jié)合在一起非常緊密,所以,它需要大量的能量來打破這種債券。Forthosewhoareinterested,theactualbonesina3-dimensionalsiliconcrystalarearrangedatequalanglesfromeachother.Ifyouvisualizeatetraheron(apyramidwiththreepointso
6、nthegroundandafourthpointstickingstraightup)withtheatomcenteredinside,thefourboneswillbedirectedtowardsthepointsofthetetrahedron.對于那些有興趣,實際的骨骼三維硅晶體排列在互相平等的角度。如果你想象tetraheron(金字塔三分,第四個點了起來)的原子為中心的內(nèi)部,這四個骨頭將指向四面體的點。Nowwehaveknownoursiliconcrystal,butwestillhaven’tknownasemiconductor.Inthecrystalwes
7、awabove,alloftheouterelectronsofallsiliconatomsareusedtomakecovalentbondswithotheratoms.Therearenoelectronsavailabletomovefromplacetoplaceasanelectricalcurrent.Thus,apuresiliconcrystalisquiteagoodinsulator.Infact,itisalmostg