EELS Electron Energy Loss Spectrum

Electron Energy Loss Spectroscopy (EELS) is a High-order component analysis detection instrument installed under a transmission electron microscope (TEM)When a high-energy electron beam penetrates the sample, it interacts with the electrons in the material's atoms.Inelastic Scattering , leading to a specific degree of energy loss for the incident electrons.

When the electron beam interacts with the atoms in the material, it may exciteCore Electrons or Valence Electronsto cause the electron beam to lose corresponding energy, by measuring and analyzing the distribution of these electron energy losses, important information about the material at the nanoscale or even atomic scale can be obtained, includingelement types, chemical bonding states, electronic structure, and band structure, etc.

In addition, EELS can also be combined withEnergy Filtered TEM (EFTEM, Energy Filtered Imaging)The technology effectively enhances image contrast by selecting electrons within a specific energy range to form images, and is used to observe the spatial distribution of specific elements or chemical states within the sample, significantly improving the analytical capability of material composition and structure.

In EELS spectra, it can usually be divided into two main analysis regions:

In electron microscopy material analysis, electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDS / EDX) are both commonly used elemental analysis techniques, which can be combined with TEM or SEM for material composition analysis. However, their analysis principles and applicable situations differ, and in practice, these two techniques are usuallycomplementary useto obtain more complete material information.

EDS mainly generates from the excitation of the sample by the electron beam.Characteristic X-rayto determine the elemental composition in materials, making it very suitable for the rapid identification of the types and distribution of elements present in the materials; while EELS measures the energy loss generated after electrons penetrate the sample.energy loss signalIn addition to elemental information, it can further analyze.Chemical bonding, oxidation state, and electronic structureto explore deeper material properties.

In addition, EELS has advantages in energy resolution and nanoscale analysis capabilities, with energy resolution reachingabout 1 eV or lowerIt can effectively distinguish overlapping element signals that are difficult to resolve with EDS, such as the signal interference of common elements in semiconductor materials.

In practical materials analysis, EELS and EDS are usuallyused in conjunctionfor example, in the analysis of semiconductor materials or nanomaterials,EDSCan quickly confirm the elemental composition of materials;EELSchemical states and electronic structures of elements can be further analyzed. Through the integration of the two techniques, a more complete understanding of the materials can be achieved.Element composition, chemical bonding, and nanoscale structural characteristicsIt has important value for advanced semiconductor processes and nanomaterial research.

MA-tek has a completeTEM / STEM / EELS integrated analysis platformelement and chemical bond analysis at the nanoscale for advanced materials and semiconductor process structures. Through high-resolution energy analysis systems and professional data analysis capabilities, it can deeply analyze the materials.element distribution, chemical bond state and electronic structureproviding highly reliable information on the microstructure of materials, EELS analysis has extremely high value in the research of nanomaterials due to its capabilities.High energy resolution, high spatial resolution, and high sensitivity to low atomic number elements.can analyze the distribution and chemical states of elements such as carbon, nitrogen, and oxygen, and perform precise element mapping and chemical bond interpretation at the nanoscale, MA-tek can throughSTEM-EELS scanning analysis and Energy-Filtered TEM technologyto establish the composition and electronic structure distribution of materials at the nanoscale, and can be applied to advanced semiconductor process materials and nanomaterials research.

Image | Energy Filtered TEM

 

Energy-filtered imaging to observe structural differences in materials.

Using Energy Filtered TEM technology, by selecting electron signals from different energy ranges, the contrast changes in the material structure can be observed. Under different energy filtering conditions, the internal structure and element distribution of the material will present different imaging characteristics.

Figure | Near Edge Fine Structure (ELNES)

 

Chemical bonding and oxidation state analysis

Using EELSNear Edge Fine Structure（ELNES）Analysis can identify different chemical bond states. The image shows the differences in the oxygen element energy spectrum of the gate oxide layer in a 16 nm semiconductor process FinFET, thereby distinguishing different oxide materials.

Image | STEM-EELS Line Scan

 

Nano-scale element distribution analysis

Combining STEM scanning with EELS spectrum analysis, line scanning can be performed along a specified path to obtain nanoscale variations in element concentration within the material, commonly used for the analysis of low dielectric materials or multilayer thin film materials in semiconductors.