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1、CHAPTER2.MicrofabricationtechnologySemi-conductorindustryandMEMSmaterials.IntroductiontomodernSemiconductorindustrySemiconductorindustryisplayingmoreandmoreimportantroleinmodernsociety.Wecansay,nosemiconductorindustry,nomoderncivilization!2)CommonlyusedM
2、EMSmaterialsCategoryMaterialPropertyorapplicationMetalAu,Al,Cu,Ni,CrConductorSemiconductorSiliconStructure,semiconductorPoly-crystallinesiliconStructure,semiconductorSingle-crystallinesiliconStructure,AnisotropicetchpropertiesGaAsStructure,opticalpropert
3、iesQuartzCrystallineSiO2Substrate,structuresPolymerParylene-CNafionPolymericmaterialsNon-metalsDiamond(C)structure3)CrystalstructureofSilicon4)Crystalplanes5)Typesofsiliconwafer①GeometricrepresentationofcrystalSiDefinition:“()”specificplane“{}”equivalent
4、plane“[]”specificdirection“<>”equivalentdirection②Wafersareclassifiedashowtheyaredoped(n-type,p-type),andhowtheSicrystalsareorientedasseenfromthetopoftheshapeofthewafersarecutdifferently.6)WhydowechoosesiliconasaMEMSstructuralmaterial?Semiconductorsareac
5、lassofmaterialswhichhavetheuniquepropertythattheirelectricalconductivitycanbecontrolledoveraverywiderangebytheintroductionofdopants.Whilethispropertycaneasilybeobservedincrystalline,polycrystalline,oramorphoussemiconductormaterials,crystallinematerialspr
6、ovidethemostreproduciblepropertiesandthehighestperformancedevicesandarealmostalwaysusedinintegratedcircuits.Dopantsareatomsthatgenerallycontaineitheronemoreoronefewerelectronsintheiroutermostshellthanthehostsemiconductor.Theyprovideoneextraelectronoronem
7、issingelectron(a"hole")comparedtothehostatoms.Theseexcesselectronsandholesarethecarriers,whichcarrycurrentinsemiconductordevices.Thekeytobuildingsemiconductordevicesandintegratedcircuitsliesintheabilitytocontrolthelocaldopingandhencethelocalelectronicpro
8、pertiesofasemiconductorcrystal.7)SemiconductorDevicesUnderstandingofhowthebasicdevicesusedICsoperateisuseful,becauseitprovidessomeunderstandingoftheobjectiveswehaveforICtechnology.ThemostcommonlyusedICdevicesare:1)PNDiodes
