化学气相沉积课件.ppt

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1、ChemicalVaporDeposition化学气相沉积要点：化学气相淀积的基本原理－过程、反应、速度CVD特点CVD装置低压CVD等离子体化学气相淀积PECVD金属有机物化学气相沉淀（MOCVD）4.1简介Hardestmat.-Damagedthehardnesssensor2.5mmhigh,grownin1daysingle-crystaldiamondgrownbyCVDC.S.Yanetal.,PhysicaStatusSolidi(a)201,R25(2004)].化学气相淀积，简称CVD(ChemicalVaporDeposi

2、tion)是把含有构成薄膜元素的一种或者几种化合物或单质气体供给基片，借助气相作用或在基片上的化学反应生成所需薄膜。gasinletgasdecompositiongasreactionsubstrateadsorptiongasexhaust定义1)气体分解方式gasdecomposition(1)thermaldeposition(2)plasmadeposition(3)photon(laser,UV)deposition2)CVD种类－accordingtotemp.,pressure,…CVDchemicalvapordepo

3、sitionAPCVDatmosphericpressure...LPCVDlow-pressure...VLPCVDverylowpressure…PECVDplasma-enhanced...LECVDlaser-enhanced...MOCVDmetal-organic...ECRCVDelectron-cyclotronresonance...VPEvapor-phaseepitaxy3)优势－advantageslowcostdielectric(poly-silicon,Si3N4,SiO2)andmetalthinfilmhigh

4、depositionratehighorlowpressurecontrolthickness,defectandresistivityhighfilmqualityLTCVDforsemiconductors,ex.,Si3N4,SiO2andepilayerlowradioactivedamageButhighdepositiontemperatureandenvironmentdamage4)沉积参数－parametersforthinfilmstructure(1)temperatureofsubstrateandchamber(2)g

5、rowthrate(3)gaspressureTheseparametersaffectonsurfacespeedoftheinvolvedatoms.OverviewnotallcomponentsarefoundinallCVDsystems:SourcegasReactsonsubstratetodepositfilm4.2化学反应类型1.热分解－Pyrolysis-thermaldecompositionAB(g)--->A(s)+B(g)ex:SidepositionfromSilaneat650oCSiH4(g)--->Si(s)

6、+2H2(g)usetodeposit:Al,Ti,Pb,Mo,Fe,Ni,B,Zr,C,Si,Ge,SiO2,Al2O3,MnO2,BN,Si3N4,GaN,Si1-xGex,...2.还原－ReductionoftenusingH2(metal,substrate)AX(g)+H2(g)<===>A(s)+HX(g)-oftenlowertemperaturethanpyrolysis-reversible=>canuseforcleaningtooex:Wdepositionat300oCWF6(g)+3H2(g)<===>W(s)+6H

7、F(g)-usetodeposit:Al,Ti,Sn,Ta,Nb,Cr,Mo,Fe,B,Si,Ge,TaB,TiB2,SiO2,BP,Nb3Ge,Si1-xGex,...3.氧化/氮化反应－Oxidation/NitritionoftenusingO2/N2AX(g)+O2(g)--->AO(s)+[O]X(g)ex:SiO2depositionfromsilaneandoxygenat450oC(lowertempthanthermaloxidation)SiH4(g)+O2(g)--->SiO2(s)+2H2(g)usetodeposit:

8、Al2O3,TiO2,Ta2O5,SnO2,ZnO,...4.置换反应－ExchangeoftenusingamoniaorwatervaporAX(