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ec ron croscopy
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on en
1. Introduction:Motivationforelectronmicroscopy.
3. SEM:ScanningElectronMicroscopy
3.1FunctionalPrinciple
3.2Examples3.3EDX(EnergyDispersiveXrayspectroscopy)
.
4.1FunctionalPrinciple
4.2Examples4.3ComparingSEMan TEM
4.4HAADF(HighAngleAnnularDarkFieldImaging)
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. o v a o n orResolution oflightmicroscopeislimited:
D
= 22.1sin
lessdiffractionforsmallerwavelenghts
possiblemagnification:~2000
[1]
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. o v a o n orDifferentapproach:useelectronsinsteadoflight
(3.7pmfor100keV)p
h=
e ectrostat c e ectromagnet c
enses
insteadofglasslenses
possiblemagnification:~2000000
[2]
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. n erac onw ma erBackscatteredelectrons
Secondar electrons
Augerelectrons
XRays
specimen phonons
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. n erac onw ma erBackscatteredelectrons
Secondar electrons
Topographyandcomposition
To o ra h
Composition XRays
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. n erac onw ma er2differentapproaches:
ac scattere an
secondaryelectrons
ransm tte e ectrons
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.ScanninElectron
Microscopy
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. unc ona r nc p eElectronsource
Condenserlens
Scancoil
Objectivelense225kV
Specimen
+Detectors
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. unc ona r nc p eElectrongun e
Condenserlens
Scancoil coils coils
Objectivelens N
Specimen
+Detectors S
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. unc ona r nc p eElectrongun
e
Condenserlens
Scancoil
Objectivelens Waveform
generator
Specimen
+Detectors Detectorsignal
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. unc ona r nc p eElectrongun
Condenserlens
Scancoil coils coils
Objectivelens
Specimen
+Detectors
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. unc ona r nc p eElectrongun e
Condenserlens
ec ron an
Lightdetectors
Scancoil
Objectivelens
Specimen
+Detectors
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. xamp esPhotoniccrystalinsiliconsubstrate Nanowires
insiliconsubstrate
WSI,D.Dorfner WSI,D.Pedone
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. nergy spers ve ys emse
e
Bremsstrahlung
XrayContinuum
Electronfillingholes
CharacteristicXrays
Informationabout
chemicalcom osition
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. nergy spers ve ys ems
N2
coldfinger
Xray
Xraycreateshole/electronpairs(3.8eVnecessaryperpair)
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. nergy spers ve ys emsAlloyofaluminumand
tungsten
[3]
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rem n er
2differentapproaches:
ac scattere an
secondaryelectrons
ransm tte e ectrons
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. unc ona pr nc p esElectron
gun
Condenserlenses
Object
e50 400kVObjectivelens
+intermediate
lens
+projectivelense
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. unc ona pr nc p esElectron
gun
Condenserlensese
Object
Objectivelens
+intermediate
lens
+projectivelense
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. unc ona pr nc p esElectron
gun
e
Condenserlensess ecimen~100nm
Object
Objectivelens
+intermediate
lens
scattered directbeam+projectivelense
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. unc ona pr nc p esElectron
gun
Condenserlenses
Object
Objectivelens
+intermediate
lens
+projectivelense
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. xamp eCrossectional analysisofa
conductornanogap device
WSI,S.StrobelWSI,D.Pedone
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. ompar sono an SEM:scanswitha
focusedpoint
TEM:illumanteswhole
sample
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. g ng e nnu ar ar e Ima in HAADF
usedinSTEM(scanningtransmissionelectronmicroscopy)
AngledependsontheatomicnumberZ:
electronintesity: 2ZI
bymessuringtheelectronintensity,whilescanningover
thesample,informationaboutthechemicalcompositio
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Thanks for your attention.
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re erence
TUMchemiedepartment:
http://www.ch.tum.de/em/emlabor/methoden/rem.htm. . . .
wikipedia:
http://en.wikipedia.org/wiki/Electron_microscopy
. . _ _
http://en.wikipedia.org/wiki/Scanning_Electron_Microscopehttp://en.wikipedia.org/wiki/Energy
dispersive_Xray_spectroscopy
. .
http://en.wikipedia.org/wiki/EELS
TransmissionElectronMicroscopy,D.B.WilliamsandC.B.Carter
Scannin electronmicrosco andXra Microanal sis G.Lowes
electronmicroscopyinsolidstatephysics,H.BethgeandJ.Heydenreich
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re erence
[1]http://en.wikipedia.org/wiki/Optical_microscope
[2]http://de.wikipedia.org/wiki/Elektronenmikroskop . . . .
