《电子显微术》PPT课件

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1、第六章扫描电子显微书LettuceField(16MDRAM)TheoryofScanningElectronMicroscopeHitachiHigh-TechnologiesCorporationNanoTechnologiesSalesDept.1.ResolutionImprovement30kV1kV0.6nm0.6nm0.5nm2.5nm3.5nm1.8nmS-5200S-5000HS-5000DevelopmentofanewUHRObj.LensNewS-4800FE-SEMResolution:1.0nm15kV1.4nm1kVConfigurationofascan

2、ningelectronmicroscopeObjectiveMovableApertureModelS-3000NSpecimenStageCRTElectronGunSEDetectorSpecimenChamberComparisonamongOM,TEMandSEM第一节结构原理扫描电镜基本上是由电子光学系统、信号接收系统、供电系统、真空系统等四部分组成。在扫描电镜中，电子枪发射出来的电子束，经三个电磁透镜聚焦后，成直径20微米~25Å的电子束。置于末级透镜上部的扫描线圈能使电子束在试样表面上做光栅状扫描。试样在电子束作用下，激发出各种信号，信号的强度取决于试样表面的形貌、受激

3、区域的成分和晶体取向。值得强调的是，入射电子束在试样表面上是逐点扫描的，像是逐点记录的，因此试样各点所激发出来的各种信号都可记录下来。给试样的综合分析带来极大的方便。SEDetectorSpecimenCRTCameraAmplifierImageSignalHighVoltageDeflectionCoilsDeflectionAmplifierVacuumPumpFilamentWehneltElectronGunAnodeCondenserLensDeflectionCoilsObjectiveLensSpecimenChamberScanningElectronBeamMag.

4、ControlConfigurationofascanningelectronmicroscopePG1PG2FilamentCondenserLensapertureOrificeNVVacuumGaugeVacuumcontroller(Real-time)VacuumconditionpresetRP1RP2DPLowVacuumConditionBSEdetectorV8V6V9V3V4V1SpecimenV5V7HighVacuumConditionV2BlockdiagramofevacuatingsystemImageSampleObjectiveLens(Illumin

5、ationSource)LumpOMCondenserLensProjectionLensScreenImageImageSampleSampleObjectiveLensElectronSourceCondenserLensDeflectionCoilsSEDetectorCRTTEMSEMFluorescentscreenScanningDifferenceamongOM,TEMandSEMFETipTungstenFilament750μmElectronSourceTypeofEmissionOperatingVacum(Pa)Brightness(A/cm2･str)Sour

6、ceSize(μm)EnergySpred(eV)LifeTime(h)TungstenFilamentThermonicFieldEmissionColdFE10-5～10-85x105108300.012.00.2502000EnergySpreadEffectofchromaticaberrationΔV=～2eVTungstenFilamentCrossoverofLowEnergyElectronsCrossoverofHighEnergyElectronsΔV=～0.2eVFETipCrossoverofLowEnergyElectronsCrossoverofHighEn

7、ergyElectronsWehneltAnodeElectronBeamV0ElectronBeamV01stAnode2ndAnodeFlashingVoltageV1V0:AcceleratingvoltageV1:ExtractionvoltageBiasVoltageControlThermionicEmissionColdFieldEmission(～6.5kV)FilamentCurrentControlFilamentCompa