Contact

Kai Bachmann
Division of Analytics
Phone: +49 351 260 - 4426

Thomas Heinig
Division of Analytics
Phone: +49 351 260 - 4426

Sabine Haser
Division of Analytics
Phone.: 03731 392255

SEM Examples

Eye catcher

Scanning Electron Microscopy (SEM)

The Scanning Electron Microscopy is a method for the high-resolution imaging of surfaces. It uses electrons for imaging, much as a light microscope uses visible light. In contrast to the light microscopy the SEM generates a much higher magnification varying between 100 and 1.000.000.


Thomas Heinig, Scanning Electron Microscope
Scanning Electron Microscope runs with the MLA-Suite software by FEI 
Foto: HZDR

Equipment Features

Applications

  • High-resolution imaging of surfaces
  • Detecting rupture types and behaviours
  • Displaying particle morphology
  • Measuring particle sizes and structures

Key Features

  • Measuring in secondary (SE) and backscattered electron contrast (BSE)
  • Electron beam resolution 1.0 nm at 30 kV (SE), 2.5 nm at 30 kV (BSE)
  • Non-destructive
  • Sample stage size: 150 mm

Sample Preparation

  • Solid, vacuum-resistant, vaporized with carbon
  • Sample types:
    • Round micropscope slides 25, 30 or 40 mm
    • Thin and thick sections 28 x 48 mm
    • Single samples 15 x 15 cm

Scanning Electron Microscopy Scheme
Scanning Electron Microscopy Scheme
Foto: HZDR/ Thomas Heinig

How does it work?

To create a SEM image a focused primary electron beam scans across a sample surface. Due to the electron bombarding secondary electrons (SE) as well as backscattered electrons (BSE) emit from the sample.

While secondary elecontrons have an energy lower than 50 eV, backscattered electrons show much higher energies.The different electrons are therefore detected by two different, energy selective detectors which convert them into signals, amplifys and visualizes them on a monitor. The result is a tremendously vivid surface image. Since secondary electrons can only be emitted from the surface the resolution of the corresponding image is very good. It ranges between 5 and 10 nm. Backscattered electrons are generated at greater depths. Therefore, the resolution of the corresponding image is significantly lower. SEM have a field depth that is much higher than the one from optical microscopes.