Laboratory for Electron Microscopy

Electron microscopy II

Electron Microscopy II lecture covers scanning electron microscopy (SEM), focused ion beam techniques (FIB), and techniques for chemical analysis.

 

Date

The lecture Electron Microscopy II will take place again in SS 2021!

 

Audit relevance

Master: By attending the lectures Electron Microscopy I and II including the corresponding practical exercises and the lecture Electron Optics, the supplementary subject Electron Microscopy (14 ECTS) can be taken.

Internship Application

The online registration for the lecture-based internship can be found here:

Internship registration

 

Table of contents

  1. Scanning electron microscopy
    1. Principle
    2. Interaction between high-energy primary electrons and solids
    3. Apparative aspects
    4. Imaging Modes
      1.     Illustration with backscattered electrons
      2.     Illustration with secondary electrons
      3.     Channeling(Orientation contrast)
    5. Cathodoluminescence
    6. Imaging with electron beam induced currents (EBIC: electron-beam induced currents)
    7. Testing electronic components
  2. Imaging and patterning with focused ion beams
  3. Analytical techniques in scanning and transmission electron microscopy
    1. Comparison of scanning and transmission electron microscopy
    2. Formation of X-rays in solids
    3. Energy dispersive X-ray analysis (EDX)
    4. Wavelength dispersive X-ray analysis (WDX)
    5. Quantitative analysis of energy and wavelength dispersive spectra
    6. Electron energy loss spectroscopy (EELS)

 

Practical exercises

Scanning electron microscopy (SEM) is used to study the structure of surfaces. With the most powerful device in the LEM, structural details with dimensions around 1 nm can be imaged in samples with good electrical conductivity. In addition to the high resolution, scanning electron microscopy is characterized by the fact that an approx. 100-fold greater depth of field is achieved than in light microscopy. Depending on the imaging mode, the topography of the surface or qualitatively the changes in chemical composition can be made visible. By using energy dispersive X-ray analysis (EDX) and wavelength dispersive X-ray analysis (WDX), spatially resolved chemical analyses can be performed.

Possible applications of SEM are in the context of damage analysis, process control, process improvement, incoming and quality control as well as metrological questions, especially in the sub-micrometer range, e.g.

  • Examination of fracture surfaces
  • Causes of wear
  • Surface coatings
  • Analysis of particles and precipitates (size, density, chemical composition)
  • Analysis of material inhomogeneities

In the exercise 4 experiments are offered, which should cover the basics of scanning electron microscopy, or treat the material of the lecture in practice:

1st experiment: Scanning electron microscopy I
2nd experiment: Structuring and imaging with focused ion beams
3rd experiment: Scanning electron microscopy II/ EDXS
4th experiment: electron energy loss spectroscopy (EELS), electron spectroscopic imaging (ESI)

You will learn more about the practical exercise in the lecture.