A new EXAFS method for the local structure analysis of low-Z elements.

Area of Science:

• Materials Science
• Surface Science
• Spectroscopy

Background:

• Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy is crucial for local structure analysis.
• Existing methods like Total Electron Yield (TEY) can be affected by secondary electron interference, especially for low-Z elements.
• Accurate elemental analysis of materials like silicon nitride requires precise EXAFS data.

Purpose of the Study:

• To propose and validate a novel analytical method, differential electron yield (DEY)-EXAFS, for local structure analysis.
• To demonstrate the method's capability in obtaining true EXAFS spectra, free from interfering signals.
• To confirm the method's efficacy for low-Z elements by analyzing a silicon nitride film.

Main Methods:

• Utilizing an electron energy analyzer to measure electron energy distribution curves at various excitation photon energies.
• Applying dual-energy windows for simultaneous measurement of Auger and background spectra.
• Subtracting background spectra from measured curves to isolate specific elemental EXAFS signals.
• Implementing the differential electron yield (DEY)-EXAFS technique.

Main Results:

• Successfully obtained the N K-edge EXAFS spectra for a silicon nitride film.
• The background subtraction effectively removed photoelectrons and secondary electron interference.
• The derived N-Si nearest-neighbor distance closely matched results from Si K-edge analysis.
• The DEY-EXAFS method provided accurate local surface structure information.

Conclusions:

• The differential electron yield (DEY)-EXAFS method is a valid and effective technique for local structure analysis.
• This method overcomes limitations of traditional methods, offering improved accuracy for low-Z elements.
• DEY-EXAFS enables precise determination of local atomic arrangements and bonding in materials.