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

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Presentation on theme: "(Electron) microscopy at MTM SIM² workshop HiTemp group – MTM Annelies Malfliet 23 January 2013."— Presentation transcript:

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 23/01/20132

3 MICROSCOPY AT MTM 23/01/20133

4 Overview microscopy 23/01/20134 FEI Nova NanoSEM New µscope

5 Core facility ‘Electron microscopy’ State-of-the-art Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) 23/01/20135

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 23/01/20136

7 Electron microscopy Difference LOM – EM – Source: light vs. electrons – Optical lenses vs. eletromagnetic lenses – Eye vs. Detectors Resolution Most used electron microscope is Scanning Electron Microscope (SEM) 23/01/20137

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 23/01/20138

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) 23/01/20139

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 D = 3 mm screen sample electron source 23/01/201310

11 Overview table ImagingPhase compositionCrystal structure/texture EDSWDSEELS Light optical microscopyx XL40 SEM LAB6xx XL 30 SEM FEGxx XL30 ESEM FEGxx XL30 SEM + EBSDxx FEI Nova Nanosemxxx JXA-8530F FEG-EPMAxx TEM CM 200 FEGxxxx 23/01/201311

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 23/01/201312

13 Effort - information map 23/01/ In general...

14 SAMPLE PREPARATION 23/01/201314

15 Sample preparation at MTM 23/01/201315

16 Sample preparation 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 grinding polishing 23/01/201316

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 23/01/ Mechanical polishingCP method Polishing time: 4 hours Au Ni-P Cu

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 23/01/201318

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 –... 23/01/201319

20 SEM XL30 FEG/XL40 LAB6 23/01/201320

21 SEM XL30 FEG Equipment details – kV – 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 LaB 6 : similar possibilities (SE/BSE, EDS,...) Particle analysis software LaB 6 vs. FEG: LaB 6 has larger probe diameter and less brightness, but for many applications it can be sufficient Almost not used XL30: BSE image + EDS analysis 23/01/ XL40: BSE image

22 FEG-EPMA 23/01/201322

23 FEG-EPMA JEOL JXA 8530F 23/01/201323

24 Main features In-Lens Schottky Field Emission Gun (FEG) – 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 MnK  – WDS system: 5 full scanner type X-ray spectrometers 23/01/201324

25 FEG-EPMA: Use Typical analysis type – Composition quantification using standards Including minor and light elements – Mapping elemental distribution – Better spectral resolution  oxidation state of elements 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 23/01/201325


27 TEM CM 200 FEG Details – kV – Resolution < nm – EDS/EELS – GATAN Tridiem Image Filter Few users Several day training 23/01/201327

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 23/01/201328

29 FEI NOVA NANOSEM 23/01/201329

30 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 23/01/ EDS+EBSD Anodized Ti


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 23/01/201332

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