1. (Electron) microscopy at MTM
SIM² workshop
HiTemp group – MTM
Annelies Malfliet
23 January 2013

2. Content Microscopy at MTM: in general Sample preparation In particular
SEM XL30 FEG/XL40 LAB6
FEG-EPMA JXA-8530F
TEM CM 200 FEG
FEI Nova NanoSEM
Contact details
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3. Microscopy at MTM
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4. Overview microscopy
New µscope
FEI Nova NanoSEM
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5. Core facility ‘Electron microscopy’
State-of-the-art Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM)
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6. (Electron) microscopy’
Imaging: phase distribution, particle size, topography, ...
Light Optical Microscopy (LOM)
Secondary Electron (SE) or Backscattered Electron (BSE) imaging (on SEM)
Bright-Field (BF) imaging (on TEM)
Chemical analysis: phase composition, presence of impurity elements, element distribution, ...
Energy Dispersive Spectroscopy (EDS) (on SEM/TEM)
Wavelength Dispersive Spectroscopy (WDS) (on FEG-EPMA)
Electron Energy Loss Spectroscopy (EELS) (on TEM)
Crystallography: crystal structure + texture
Electron Backscatterd Diffraction (EBSD) (on SEM)
Selected Area Electron Diffraction (SAED) or Convergent Beam Electron Diffraction (CBED) (on TEM)
 Broad spectrum of equipment and preparation facilities
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7. Electron microscopy Difference LOM – EM Resolution
Source: light vs. electrons
Optical lenses vs. eletromagnetic lenses
Eye vs. Detectors
Resolution
Most used electron microscope is Scanning Electron Microscope (SEM)
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8. SEM detectors Typical detectors
Secondary electron detector (SE)
Good spatial resolution
Topography
Backscattered electron detector (BSE)
Strong atomic number contrast
X-ray detector
Elemental analysis
Different signals originate from different interaction volumes
Effect of voltage on interaction volume
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9. Composition analysis
Based on emission of characteristic X-rays caused by excitation from eletron beam
X-ray can be detected by:
Energy Dispersive Spectroscopy
X-ray are separated based on their energy
Result is an energy-intensity spectron with peaks
Peak position identifies the element
Height ~ its concentration (standardless quantification)
Energy resolution ~127eV
Measuring time: s (all elements measured at the same time)
Wavelength Dispersive Spectroscopy
not on SEM, but on Electron Probe Micro Analysis (EPMA)
Higher spectral resolution
Typically quantification with standards
More time consuming (5 spectrometers  up to 5 elements measured at the same time)
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10. SEM - TEM Difference SEM – TEM
Higher eV with TEM  beam with smaller wavelength  higher spatial resolution
Observe electrons passed through (and interacted with) the sample
Much smaller and especially thinner sample
electron source
D = 3 mm
sample
screen
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11. Crystal structure/texture
Overview table
Imaging
Phase composition
Crystal structure/texture
EDS
WDS
EELS
Light optical microscopy x
XL40 SEM LAB6
XL 30 SEM FEG
XL30 ESEM FEG
XL30 SEM + EBSD
FEI Nova Nanosem
JXA-8530F FEG-EPMA
TEM CM 200 FEG
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12. Effort - information Microscopy technique is mainly determined by
What information you would like to have
Size of the features of interest
Depending on technique, material and required sample ‘perfectness’, the parameters that determine effort are:
Sample preparation
Embedding: 15 min – 1 day curing/ conductive resin (under pressure)
Grinding/polishing: hard/brittle/porous/soluble in water(ethanol)/...
Conductive coating needed: thickness, homogeneity
Preventing contamination (air, moisture): storing in desiccator/vacuum/cryo cleaner/...
Removing contamination: plasma cleaner/...
Learning process
Training
Experience/practice!
Literature reading
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13. Effort - information map
In general ...
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14. Sample preparation
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15. Sample preparation at MTM
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16. Sample preparation In general: for LOM/SEM/EBSD (room 02.33) Cutting
grinding
In general: for LOM/SEM/EBSD (room 02.33)
Cutting
Ultrasonic cleaning: remove particles from pores
Embedding with
Technovit: cures very fast (15 min)
Epofix: better infiltrates pores  better for powder or porous material (1 day curing under vacuum)
Predopress (pressure/hot mounting): harder resin  better for harder materials (also conductive powder available for conductive resin  no need for coating in case of conductive sample)
Grinding/polishing/OPS
Manual or automatic
Cooling + removing debris: water/ethanol/oil
OPS: soft/ductile materials
Different materials require different grinding + polishing procedure  best to talk with responsible technician
polishing
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17. Sample preparation
Especially for evaluation of interfaces or for soft material: Cross section ion polishing
Clean surface on large area (~ 1 mm²)
Disadvantage: more time consuming than mechanical polishing Au
Ni-P Cu
CP method
Polishing time: 4 hours
Mechanical polishing
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18. Sample preparation Etching (for metals)
In acid, electrolytically
Coating with C/Au/Pt/Au-Pd/Pt-Pd
Au-Pd: imaging surface topography/gives higher resolution
C: Chemical analysis, mapping, EBSD
Carbon rod: better suited for thin homogeneous layer than carbon wire
For EDS/WDS: Pay attention to overlap of peaks of coating and sample
Degassing in vacuum chamber
Coating units at MTM
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19. Sample preparation
TEM: more complicated + different methods depending on material
Separate TEM sample preparation room at MTM
Possible at MTM
Thin film: grinding/polishing/thinning/breakthrough (electrolytic,ion miller)
Replica method
Depositing on support grid
Ultramicrotome to cut slices
FIB
...
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20. SEM XL30 FEG/XL40 LaB6
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21. SEM XL30 FEG Equipment details Most frequent used EMkV
SE/BSE detector
EDS (detection from B)
Most frequent used EM
User-friendly
Many users
1 day training
Reservation per 2 hour
1-3 samples
Many users  highly occupied (24h/d; 7d/w)
Alternative is SEM XL40 LaB6:
similar possibilities (SE/BSE, EDS, ...)
Particle analysis software
LaB6 vs. FEG: LaB6 has larger probe diameter and less brightness, but for many applications it can be sufficient
Almost not used
XL30: BSE image + EDS analysis
XL40: BSE image
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22. FEG-EPMA
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23. FEG-EPMA JEOL JXA 8530F
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24. Main features In-Lens Schottky Field Emission Gun (FEG) Imaging
kV, 50 pA – 500 nA, 40 nm minimum probe size
Imaging
Electron detectors: SE + BSE
40x to 300,000x magnification
Cathodeluminescence system
Monochromatic + panchromatic
Phase composition
EDS system: Resolution: 129 MnKa
WDS system: 5 full scanner type X-ray spectrometers
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25. FEG-EPMA: Use Typical analysis type 0.5-1 day/sample 3-day training
Composition quantification using standards
Including minor and light elements
Mapping elemental distribution
Better spectral resolution  oxidation state of elements
0.5-1 day/sample
Possible to let it run overnight by setting measurement points or mapping area
3-day training
Users are through promotors of the FEG-EPMA
For external and occasional measurements, technical responsible at MTM can do the measurement
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26. Transmission Electron microscopy (TEM)
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27. TEM CM 200 FEG Details Few users Several day training 20-200 kV
Resolution < nm
EDS/EELS
GATAN Tridiem Image Filter
Few users
Several day training
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28. TEM: Use
Characterization of nanoscale particles with respect to their shape, size, structure, chemical composition and distribution.
Imaging
Diffraction: crystal structure
Composition analysis
EDS
EELS: especially useful for light elements
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29. FEI Nova NANOSEM
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30. FEI Nova Nanosem FEI Nova Nanosem
Imaging (SEM with TLD)
High resolution
Low keV imaging
‘Pure’ samples (not coated)
Difficult samples (magnetic, non-conductive)
Chemical analysis (EDS)
Phase/ texture analysis (EBSD)
Chrystallographic characterisation
Integration with EDS  phase analysis
Plasmacleaner
Just installed, about to be operational
Anodized Ti
EDS+EBSD
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31. What if you would like to use one of the microscopes at MTM?
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32. Contact details For more information:
Core facility Electron microscopy: Tom Van der Donck
SEM XL30/XL40: Rudy De Vos
If you are advised to have a training, use the training request form available at
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