集成电路制造工艺课件04_氧化

《集成电路制造工艺课件04_氧化》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、2013-10-12ApplicationofSiliconDioxide•OxideinaMOSFETpassivationoxideOxidationandSi/SiO2interfaceisolationoxideImplantmaskgateoxide•OxideinIC-Insulatingbetweenconductionlayers-IsolateadjacentdevicesProf.MingxiangWANG-Maskinglayerinvariousprocesses•Highresistivity>1020Ω-cm•Highbreakdownelect

2、ricfield>10MV/cm•Largeenergybandgap:Eg~9eV2/23StructureofSiOFilms2•Basicunit:SiO44-tetrahedra•Quartzcrystal---orderednetworkofbasicunitSiO44-•SiO2filmsinIC---amorphousstate•Nolongrangeorder,withshortrangeorder(similartoglass)•Verystable,goodSi/SiO2interfaceInterlayerdielectricoxygensilicon

3、IsolationCrystallineSiO2(quartz)=2.65g/cm3AmorphousSiO(thermaloxide)=2.2g/cm3schemes23/234/2312013-10-12ThermalOxidationofSiliconOxidationFurnaceChemicalreactionofthermaloxidation–Dryoxidation:Si(s)+O2(g)SiO2(s)–Wetoxidation:Si(s)+2H2O(g)SiO2(s)+2H2(g)--Typicallycarriedoutat700-1200℃oxid

4、eformed@interface–Oxidequalitydependson:•Substratepurity(wafercleaning)•Gaspurity•Oxidationprocess–Wetoxidationismuchfaster,H2OmoleculeissmallerthanO2andeasiertodiffusethroughSiO2film,solubility3GasoptionsofH2OinSiO2is~10higherthanO25/236/23SiConsumptionCharacteristicsofOxidationoriginalsu

5、rfacetoxSiO2-DryoxidationtendstoproducebetteroxidequalityandSi/SiO2interface.SiSi-GoodinterfacebetweenSi/SiO2makeSitechnologysuperioroverothersemiconductormaterialsofchoice•NumberofSiatomsdoesnotchange-Inwetoxidation,usuallya5-minutedryoxidationbeforetSiNSi=toxNoxandafterwetoxidationisadde

6、dtoimproveoxidequalityNSi---SidensityinSi(=5x1022atoms/cm3)“dry-wet-dry”scheme-Afteroxidation,thereactionshouldbestabilizedbyNox---SidensityinSiO2(=2.2x1022atoms/cm3)annealingininertambient(N2orAr)toallowsomelocal22atomsre-arrangementwithoutfurtherSiO2formation.2.2101unitIthelpstoreducein

7、terfacetrapsandfixedcharges.tt0.44tsiox51022ox“dry-wet-dry-anneal”scheme-Besidesthermaloxidation,LPCVD/PECVDcandeposit-Siisconsumedinoxidationinaratioof0.44unitofSioxidefilmwithpoorerqualitythicknesstoform1unitofoxidethickness7/238/2322013-10-12BasicModelfo