Elektronenscan

Elektronenscan refers to a technique in which a focused beam of electrons is scanned across a surface and the resulting signals are recorded as a function of position. The process yields spatially resolved information about surface topography, composition and, in some cases, crystallographic structure. Elektronenscan is most commonly realized in scanning electron microscopy (SEM) and in electron probe microanalysis (EPMA).

Principle and signals: An electron source generates a narrow beam that is steered and focused by magnetic and electrostatic lenses. The beam raster-scan over the specimen while detectors collect signals such as secondary electrons, backscattered electrons, and characteristic X-rays. Secondary-electron signals provide high-resolution topographic detail; backscattered electrons give compositional contrast related to atomic number; X-ray detectors enable elemental mapping or quantitative microanalysis. In some systems, additional techniques such as electron backscatter diffraction (EBSD) provide crystallographic information.

Equipment and samples: Elektronenscan typically requires a high-vacuum environment. Samples may need conductive coating or low beam energies to mitigate charging, especially for non-conductive materials. Operating parameters, including accelerating voltage, spot size, and scan speed, are chosen to balance resolution, signal-to-noise, and potential beam damage. Data are generated as images, spectra, or diffraction patterns and can be correlated for multifaceted analysis.

Applications and limitations: The method is widely used in materials science, metallurgy, semiconductor inspection, geology and biology-related surface studies. It enables detailed surface imaging, elemental mapping, and structural analysis. Limitations include potential beam-induced damage, charging for insulators, and the need for vacuum and specialized sample preparation.