Use of reciprocal lattice layer spacing in electron backscatter diffraction pattern analysis

Area of Science:

• Materials Science
• Crystallography
• Electron Microscopy

Background:

• Electron backscatter diffraction (EBSD) is a powerful technique for analyzing crystal structures.
• Reciprocal lattice layer spacing is crucial for phase identification in materials.

Purpose of the Study:

• To adapt and validate a method for measuring reciprocal lattice layer spacing using EBSD.
• To improve the accuracy of EBSD-based layer spacing measurements, particularly for high atomic number materials.

Main Methods:

• Utilizing higher-order Laue zone (HOLZ) rings in EBSD patterns to derive layer spacing.
• Adapting principles from convergent-beam electron diffraction (CBED) in transmission electron microscopy (TEM).
• Implementing an extrapolation procedure using measurements at various accelerating voltages for enhanced accuracy.

Main Results:

• The EBSD technique successfully measures reciprocal lattice layer spacing for phase identification in many materials.
• A significant improvement in accuracy was achieved for higher atomic number materials using the extrapolation method.
• The method was successfully applied to analyze two polytypes of silicon carbide (SiC).

Conclusions:

• EBSD-based reciprocal lattice layer spacing measurements are a valuable tool for materials characterization.
• The developed extrapolation procedure enhances the reliability of EBSD for complex materials.
• This technique offers a robust method for analyzing polytypes and identifying phases in materials like SiC.