MOS--最详细的介绍

PowerMOSFETBasicandApplicationSongLiu
MOSFET:MetalOxideSemiconductorFieldEffectTransistorisathree-terminaldeviceswhichinbasictermbehavesasavoltagecontrolledswitch（压控）.
氧化层MetalLayer：门极(现在多晶硅Polysilicon形成门极）
氧化隔离层OxideIsolationLayer：防止电流在门极和其它两电极间D、S极流动，但并不阻断电场ElectricField.
半导体层SemiconductorLayer：取决于门极电压，阻止或允许电流在D/S间流通MOSFETBasic间流通DrainSourceGateDrainGateSourceCircuitSymbolPackagePinLayout
MOSFET半导体特征半导体特征半导体特征半导体特征MOS是多子单极型器件(无少子),受温度影响小,PMOS多子是空穴,NMOS多子是电子,MajorityCarrier.反转层:InversionLayerDMOS:双重扩散MOS,DoubleDiffused氧化层相当于介电质DielectricMaterial(Dielectricconstant)掺杂Doged,高掺杂浓度区域Heavilydopedregion半导体层：依赖于门极电压，阻断或允许电流在漏极D和源极S间流MOSFETBasic半导体层：依赖于门极电压，阻断或允许电流在漏极D和源极S间流动
1.平面横向（Lateral）导电型MOSFET管增加或减少门极电压会增大或减少N沟道的大小，以此控制器件导通没有充分应用芯片的尺寸，电流和电压额定值有限CMOS工艺，适合低压信号管，如微处理器，运放，数字电路低的电容，快的开关速度SignalMOSFETStructureVddDSGLoadDriver沟道沟道SinversionlayerD-MOSFETStructure
2.平面垂直导电型功率MOSFET管D-MOSFET(VDMOSFET)：VerticalDouble-diffusedMOSFET，垂直导电双扩散，70年代商业应用平面Planar门极结构：n-typechannelisdefinedbythedifferenceinthelateralextensionofthejunctionsunderthegateelectrode.ThevoltageblockingcapabilityisdeterminedbythedopingandthicknessoftheN-driftregion.多个单元结构。具有相同RDS(on)电阻MOSFET并联，等效电阻为一个多个单元结构。具有相同RDS(on)电阻MOSFET并联，等效电阻为一个MOSFET单元RDS(on)的1/n，裸片面积越大其导通电阻越低。Thedriftregionresistanceincreasesrapidlywithincreasingblockingvoltage。Double-diffused？？
2.平面垂直导电型功率MOSFET管D-MOSFETStructureD-MOSFETStructure
2.平面垂直导电型功率MOSFET管Thechannellengthofthisdevicecouldbereducedtosub-microndimensionsbycontrollingthediffusiondepthsoftheP-baseandN+sourceregionswithoutresortingtoexpensivelithographytools.ThedevicefabricationprocessreliedupontheavailableplanargatetechnologyusedtomanufactureCMOSintegratedcircuits.ThefastswitchingspeedandruggednessoftheD-MOSFETstructureweresignificantadvantagescomparedwiththeperformanceoftheavailablebipolarpowertransistorLVMOSRDSONisconstrainedbythesignificantchannelresistanceduetothelowLVMOSRDSONisconstrainedbythesignificantchannelresistanceduetothelowchanneldensityandtheJFETregioncontribution.JFETregionsubstantiallyincreasestheinternalresistanceU-MOSFETStructure
3.沟槽垂直导电型MOSFET管V型沟槽：不容易生产，V尖角容易形成高的电场.U型沟槽：U-MOSFET结构90年代商业化应用，平面型的演变，切开翻转90度。Silicon表面刻沟槽，TheN-typechannelisformedontheside-wallofthetrenchatthesurfaceoftheP-baseregion.ThechannellengthisdeterminedbythedifferenceinverticalextensionoftheP-baseandN+sourceregionsascontrolledbytheion-implantenergiesanddrivetimes。栅结构不与裸片表面平行而是构建在沟道之中垂直于表面，因此占用空间较少且使电流流动真正垂直，最小化基本单元面积(cellpitch小)，在相同的占位空间中可以集成更多的单元从而降低RDSON.U-MOSFETstructurereducetheon-stateresistancebyeliminationoftheJFETcomponent.U-MOSFETstructurereducetheon-stateresistancebyeliminationoftheJFETcomponent.无JFETregion电流流动垂直
3.沟槽垂直导电型MOSFET管Thesmallercellpitchincreasesthechanneldensity.However,theelectricfieldatthejunctionJ1betweentheP-baseregionandtheN-driftregionislargewhichpromotestheextensionofthedepletionregionintotheP-baseregion.Consequently,thechannellengthmustbemaderelativelylargeinordertosuppressreachthroughbreakdownwhichincreasesthechannelresistance.ThelargeelectricfieldatthejunctionproducesalargeelectricfieldinthegateoxideinthetrenchesespeciallyatthecornersintheU-MOSFETstructure.Thiscreatesreliabilityconcernsduetogenerationofhot-electrons.TheroundedsurfacesattheU-MOSFETStructurereliabilityconcernsduetogenerationofhot-electrons.Theroundedsurfacesatthebottomofthetrenchcanreducethisproblem.Buttheelectricfieldinthegateoxideisrelativelylarge.Thehighinputcapacitanceandhighreversetransfercapacitanceoffsetsthebenefitsofthelowspecificon-resistanceinhighfrequencyapplications.Thiscapacitancecanbereducedbyselectivelyincreasingtheoxidethicknessatthebottomofthetrenchsurface.Thisaddssignificantcomplexitytothedevicefabricationprocess.U-MOSFETStructureRoundedtrenchbottomsurfaceThickeroxideatthetrenchbottomsurfaceSGT-MOSFETStructure
Thedepthofthetrenchmustbetailoredtoachievethedesiredbreakdownvoltage.ThesurfaceofthetrenchmustbesmoothandfreeofdamageinordertoobtainagoodMOSinterfacewithhighchannelinversionlayermobility.
Athickoxideisgrownonthetrenchsurfacebythermaloxidation.Theoxidethicknessmustbesufficienttoprovidethedesiredchargecouplingaswellastosupporttheentiredrainblockingvoltage.
ThetrenchisthenrefilledwithhighlydopedN-typepolysilicon(itisetcheduntilitisrecessedbelowthesurfacetoadepthslightlybelowthedepthoftheP-baseregion).
Afreshoxideisthengrownbythermaloxidation
Afreshoxideisthengrownbythermaloxidationonthetrenchsidewallstoformthegateoxide.Athickeroxideissimultaneouslyformedbythethermaloxidationonthetopsurfaceofthepolysiliconinsidethetrenchesasanisolationoxidebetweenthegateelectrodeandthesourceelectrode.Asecondpolysiliconlayerisnowdepositedandplanarizedtoserveasthegateelectrode.SGT-MOSFETStructure
ThedepletionregionsareformedacrossthehorizontaljunctionJ1andtheverticaltrenchsidewall.Thistwo-dimensionaldepletionalterstheelectricfielddistributionfromthetriangularshapeobservedinconventionalparallel-planejunctionstoauniformdistributionduetothelineardopingprofile.Thisallowssupportingarequiredblockingvoltageover