半导体器件原理.ppt

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1、CarrierTransportPhenomenamobilityresistivityRecombinationprocesses—mobilityVd=E-迁移率，表示单位场强下电子的平均漂移速度（cm2/V·s)I=-nqVd1sJ=-nqVd=-nqESi:n=1350cm2/V·s,p=500cm2/V·s—mobilityGe,Si:声学波散射（晶格振动）和电离杂质散射声学波散射：电离杂质散射：总迁移率：—mobilityIII-V族：除共价键外，还有离子键成分，长纵光学波有重要的散射作用—resistivityJ=E=nqnE+pq

2、pE—Recombinationprocessesnpni2（注入、抽取）np=ni2非平衡载流子非平衡载流子的复合：（1）直接复合：电子在导带和价带之间的直接跃迁，引起电子和空穴的直接复合（2）间接复合：电子和空穴通过禁带的能级(复合中心）进行复合—Recombinationprocesses直接复合—Recombinationprocesses间接复合的四个过程甲-俘获电子；乙-发射电子；丙-俘获空穴；丁-发射空穴。（a)过程前(b)过程后—RecombinationprocessesrecombinationrateU(cm-3/s,单位时间、单位体积复合

3、掉的电子-空穴对数):lifetime（小注入）SiGeHBTtechnologyforcircuitapplicationSemiconductorFabricationSiGeHBTTheSiGeHBTsusedwerefabricatedbyIBM,andaretypicaloffirst-generationSiGetechnology.Aschematiccross-sectionisshowninFigure.TheSiGeHBThasaplanar,self-alignedstructurewithaconventionalpolyemittercon

4、tact,silicidedextrinsicbase,anddeep-andshallow-trenchisolation.TheSiGebasewasgrownusingUHV/CVD.Thep-typesubstrateandthen-p-nlayersoftheintrinsictransistorforman-p-n-pmulti-layerstructure,thep-typesubstrateisusuallybiasedatthelowestpotential(5.2Vhere)forisolation.BipolarMOSFETMOSFETMOSF

5、ETcircuittechnologyhasdramaticallychangedoverthelastthreedecades.Startingwithaten-micronpMOSprocesswithanaluminumgateandasinglemetallizationlayeraround1970,thetechnologyhasevolvedintoatenth-micronself-aligned-gateCMOSprocesswithuptofivemetallizationlevels.Thetransitionfromdopantdiffusi

6、ontoionimplantation,fromthermaloxidationtooxidedeposition,fromametalgatetoapoly-silicongate,fromwetchemicaletchingtodryetchingandmorerecentlyfromaluminum(with2%copper)wiringtocopperwiringhasprovidedvastlysuperioranaloganddigitalCMOScircuits.Figure:Cross-sectionalviewofaself-alignedpoly

7、-silicongatetransistorwithLOCOSisolation0.25mCMOS工艺工艺1工艺2Technology晶体生长与外延氧化与薄膜淀积扩散与离子注入光刻—图形曝光与刻蚀Technology晶体生长与外延—从熔体中生长单晶：直拉法(Si)和布里奇曼法(GaAs)原材料：石英砂SiC(固体)+SiO2(固体)Si(固体)+SiO(气体)+CO(气体)冶金级硅电子级硅（ppb量级）硅片成形:前处理切片双面研磨抛光—介质淀积常压化学气相淀积（APCVD)低压化学气相淀积（LPCVD)等离子增强化学气相淀积(PECVD)：(因素：衬底