《电子显微术》PPT课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,*,第三级,第四级,第五级,第六章 扫描电子显微书,Lettuce Field(16M DRAM),Theory of Scanning Electron Microscope,Hitachi High-Technologies Corporation,Nano Technologies Sales Dept.,1.Resolution Improvement,30kV,1kV,0.6 nm,0.6 nm,0.5 nm,2.5 nm,3.5 nm,1.8 nm,S-5200,S-5000H,S-5000,Development of a new UHR Obj.Lens,New S-4800 FE-SEM,Resolution:,1.0nm 15kV,1.4nm 1kV,Configuration of a scanning electron microscope,Objective Movable Aperture,Model S-3000N,Specimen Stage,CRT,Electron Gun,SE Detector,Specimen Chamber,Comparison among OM,TEM and SEM,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25,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。,SE Detector,Specimen,CRT,Camera,Amplifier,Image Signal,High Voltage,Deflection,Coils,Deflection Amplifier,Vacuum Pump,Filament,Wehnelt,Electron Gun,Anode,Condenser,Lens,Deflection,Coils,Objective Lens,Specimen,Chamber,Scanning Electron Beam,Mag.Control,Configuration of a scanning electron microscope,PG1,PG2,Filament,Condenser Lens aperture,Orifice,NV,Vacuum,Gauge,Vacuum controller,(Real-time),Vacuum,condition preset,RP1,RP2,DP,Low Vacuum,Condition,BSE detector,V8,V6,V9,V3,V4,V1,Specimen,V5,V7,High Vacuum,Condition,V2,Block diagram of evacuating system,Image,Sample,Objective,Lens,(Illumination Source),Lump,O M,Condenser,Lens,Projection,Lens,Screen,Image,Image,Sample,Sample,Objective,Lens,Electron Source,Condenser,Lens,Deflection,Coils,SE Detector,C R T,T E M,S E M,Fluorescent,screen,Scanning,Difference among OM,TEM and SEM,FE Tip,Tungsten Filament,750,m,Electron Source,Type of Emission,Operating Vacum(Pa),Brightness(A/cm,2,str),Source Size(,m),Energy Spred(eV),Life Time(h),Tungsten Filament,Thermonic,Field Emission,Cold FE,10,-5,10,-8,5x10,5,10,8,30,0.01,2.0,0.2,50,2000,Energy Spread,Effect of chromatic aberration,V=,2eV,Tungsten Filament,Crossover of,Low Energy,Electrons,Crossover of,High Energy,Electrons,V=,0.2eV,FE Tip,Crossover of,Low Energy,Electrons,Crossover of,High Energy,Electrons,Wehnelt,Anode,Electron Beam,V,0,Electron Beam,V,0,1st Anode,2nd Anode,Flashing Voltage,V,1,V,0,:Accelerating voltage,V,1,:Extraction voltage,Bias Voltage,Control,Thermionic Emission,Cold Field Emission,(,6.5kV),Filament Current,Control,Filament,Comparison of electron guns,In-Lens Type(S-5200),Primary Beam,Lens,SE Detector,Specimen,Theory of Scanning Electron Microscope,Out Lens Type(W-SEM,S-4300),Primary Beam,Lens,Specimen,SE Detector,Snorkel Type(S-4700&S-4800),SE Detector,(Upper),Specimen,Lens,Primary beam,SE detector,(Lower),The illumination angle(,)of a scanning electron microscope,Focal Length,Objective Lens,Objective Movable Aperture,Specimen,Working Distance,Electron Source,Electron Beam,Lens,Primary beam,Upper,High Resolution,Lower,Topographic Image,Non Conductive Samples,Select Upper andLower Detectors,Primarybeam,Lens,SEDetector,Specimen,)In-lenstype,Primarybeam,SEDetector,Lens,Specimen,)Conventionaltype(Out-Lens),SEDetector,(Upper),Specimen,Lens,Primarybeam,)Snokeltype,SEDetector,(Lower),Hi-SEM,S-4300,S-4700,S-5200,Primary Electron Beam,Reducing charge-up with Natural-SEM,e,e,Objective Lens,BSE Detector,Residual Gas,High Pressure,(1.0Pa,270Pa,）,Non Conductive,Specimen,Astigmatism correction method,Beam Diameter,Before correction,Objective Lens,Electron Source,Electron Beam,X,Y,Electron Beam,Electron Source,Objective Lens,Stigmator,After correction,Y,X,Stigmator,Beam Diameter,Photomultiplier,Primary Electron Beam,Specimen,Photons,Light Guide,Signal,CRT,+10kV,Secondary,Electron,Scintillator,Phosphors,Al Coating Layer,Secondary electron detection system,Photo Multiplier Tube,第二节分辨率和放大倍数,一、分辨率,扫描电镜的分辨率有两重意义：对微区成分而言，它是指能分析的最小区域；对成像而言，它是指能分辨两点之间的最小距离。这两者主要决定入射电子束的直径，但并不直接等于直径。二是由所接收信号的激发区域半径决定。,二、放大倍数,扫描电镜的放大倍率,M,取决于显像管荧光屏尺寸,S,2,和入射束在试样表面扫描距离,S,1,之比，即,三、入射电子在试样内的激发区域,入射电子在被散射或吸收之前，将在试样表面下的某个距离,R,范围内运动，并激发各种射线。这些射线的能量或穿透能力各不相同，只有一定深度一定能量的射线才能逸出表面，被检测到。对于一般元素而言，电子束与试样作用，激发区域是一个梨形作用区。对重金属而言，此激发区域是一个半球形区域。不同的信号来自此激发区内不同的深度。,Backscattered,Electron,Secondary Electron,Sample(Metal),Vaccum,Simons,et.al,SE,Primary Electron Beam,BSE,Specimen,特征,X,射线,荧光,X,射线,俄歇电子,d,Z,B,Z,X,Z,F,R,B,R,X,R,F,各种信号发生的深度（,Z）,和广度（,R）,Secondary Electrons,Carrying Surface Information,Of Specimen,一,一,一,一,一,一,一,一,一,一,一,一,一,一,一,Z,Excitation Depth,for Secondary,Electron Emission,一,一,一,Secondary,Electrons,SE,SE,Secondary Electrons,Carrying Inner Information,Of Specimen,Primary Electron Beam,BSE,Backscattered,Electrons,Specimen,SE and BSE emitted from solid sample,1kV,2kV,3kV,10,20,30,40,50,(nm),BeamInvadingdepth,Theory of Scanning Electron Microscope,Primary Electron Beam,Secondary,Electron,Backscattered,Electron,Cathodeluminescence,Specimen,Current,Transmitted,Electron,Electron Beam,Induced Current,Secondary,Electron Detector,10nm,(Excitation Volume for,Secondary Electron Emission),Transmitted,Electron,(Scattered),Characteristic X-Ray,The primary electron beam-specimen,interac