The Evolution of SEM-EDS Systems: From Basic Detectors to Advanced Analytical Tools
Scanning Electron Microscopy (SEM) is often paired with energy dispersive spectroscopy (EDS) to examine a variety of materials, from batteries and ceramics to semiconductors, metals, and more. SEM-EDS can be used to investigate both the micro- to nanostructure of these materials in tandem with their composition, providing critical insights into both research and development and manufacturing processes.
An Overview of SEM-EDS Systems
SEMs are commonly equipped with an EDS detector to enable investigators to pair ultrahigh resolution imaging with non-destructive chemical analysis. The basics of these two highly complementary techniques are as follows:
- SEM: An imaging technique that uses a high-energy electron beam to characterize materials with up to sub-nano-scale resolution. Secondary and backscattered electrons, generated as a result of the interaction between the electron beam and a sample, provide information about the sample’s surface morphology, structure, and composition.
- EDS: Measures X-rays produced by a sample as a result of electron beam irradiation. The energy of each X-ray is characteristic of the element it is generated from. This allows EDS to be used to assess the composition of samples and estimate the abundance of each element present. EDS is a non-destructive technique and, when paired with SEM, can be used to analyze samples with 10-100 μm analytical resolution.
The History of SEM-EDS Systems
SEM was invented in the 1930s and reached the commercial market in the 1960s. First developed as a stand-alone imaging technique, SEM revolutionized the way that scientists could view and characterize materials. Electron microscopy technology advanced rapidly over the next decade, including the seminal integration of EDS with electron microscopy in 1968. In the decades to follow, EDS became commercially available for integration with SEM, greatly extending SEM’s capabilities to enable both high-resolution imaging and paired chemical analysis.
Advancements in SEM-EDS Systems
Like other technologies, SEM-EDS has advanced orders of magnitude in the past several decades. Analog scan generators became digital, field emitter sources improved resolution, detectors are faster and more sensitive, and software makes these systems approachable for even novice users.
Of the numerous achievements in SEM-EDS technology, some of the greatest innovations include:
- Better resolution: Continuous advancements in electron optics technology have significantly improved the resolution and sensitivity of SEM. In particular, field emission (FE) SEM has emerged as the flagship solution for ultrahigh resolution imaging. With sub-nm resolution, FE-SEM permits unprecedented observation of insulating and beam sensitive materials as well as outstanding imaging resolution for characterizing nanoscale features.
- Improved EDS technology: Like electron optics, EDS technology has advanced exponentially over the last several decades. The development of silicon drift detectors (SDD) greatly improved the sensitivity of EDS, permitting faster analyses even at lower accelerating voltages and probe currents.Similarly, the replacement of beryllium windows with thinner polymer windows or, even more recently, windowless designs have allowed for improved sensitivity, especially for low-energy X-rays. This has enabled the detection of elements as light as beryllium (with a polymer window) or even lithium (with a windowless design). The sensitivity of modern EDS detectors, in particular windowless detectors, has significantly improved analytical resolution to allow for EDS analyses and the mapping of 10s nm-scale features.
- Variable Pressure: The ability to introduce air or an inert gas into a SEM chamber to reduce charge build-up on insulating samples has allowed for the examination of a wider range of materials. While insulating materials like polymers or biologic specimens previously needed to be coated with a thin layer of a conductive material (such as gold or platinum) for SEM-EDS, the fast transition to low vacuum/variable pressure mode on modern SEMs now allows for the full characterization of these materials in their natural state.
- Ease of use: Modern SEM-EDS systems are equipped with sophisticated software that enhances image processing, data analysis, and interpretation. Machine learning algorithms and automated analysis tools have streamlined the workflow, reducing manual effort and increasing accuracy. This software also allows for more complex data visualizations and interpretations, making it easier to extract meaningful insights.
- Integration with other techniques: Other recent innovations include the direct integration of SEM-EDS with other analytical techniques, such as focused ion beam (FIB), X-ray fluorescence (XRF), or Raman spectroscopy. These hybrid systems are the ultimate analytical workstations, providing a comprehensive understanding of materials and their properties on a single platform.
Our Contribution to EDS Systems: The Gather-X Windowless EDS
If you are interested in an EDS device, JEOL would like to recommend our own state-of-the-art EDS system: The Gather-X Windowless EDS. This detector can identify characteristic X-rays that are <1 keV, permitting the direct observation of elements as light as lithium. Gather-X offers best-in-class sensitivity, allowing for EDS analysis at lower accelerating voltages and probe currents. This enables unmatched EDS spatial resolution for the analysis and mapping of nm-scale features. Visit our website to learn more about
the Gather-X Windowless EDS.
Explore the Capabilities of SEM-EDS Systems
SEM-EDS systems have come a long way since their inception, evolving into powerful tools that offer unparalleled imaging and analytical capabilities. The integration of high-resolution imaging with precise elemental analysis has transformed research and industry, providing critical insights into micro and nanoscale worlds. As technology continues to advance, SEM-EDS systems will undoubtedly play an even more pivotal role in scientific discovery and technological innovation.
Uncover more about SEM-EDS systems on our website. There, we have a variety of resources about SEM-EDS. These range from articles on its application in
material analysis to how it can be used for
elemental mapping. You can also browse our
SEM technologies to see if any devices catch your attention.