X-ray topography using the forward transmitted beam under multiple-beam diffraction conditions

Area of Science:

• Materials Science
• Crystallography
• Solid State Physics

Background:

• Dislocation imaging is crucial for understanding crystal defects.
• Traditional X-ray topography methods have limitations in resolution and speed.
• Sapphire wafers are important single crystals in various technological applications.

Purpose of the Study:

• To develop and demonstrate an advanced X-ray topography technique for high-resolution dislocation imaging.
• To visualize individual dislocations in single crystals with high dislocation densities.
• To analyze dislocation characteristics, including Burgers vector determination.

Main Methods:

• Utilizing forward transmitted synchrotron X-ray beams.
• Employing two-dimensional electronic arrays with 1 μm spatial resolution for detection.
• Performing X-ray topography under multiple-beam diffraction conditions (two-wave and six-wave approximation).

Main Results:

• X-ray topographs of a [0001] sapphire wafer showed no shape deformation or position shift of dislocation lines.
• The technique successfully visualized individual dislocations in single crystals up to a density of 1 × 10^5 cm⁻².
• Burgers vectors of individual dislocation lines were determined, similar to conventional Lang topographs.

Conclusions:

• The developed X-ray topography technique offers high parallelism and sensitivity for precise dislocation visualization.
• This method enables the study of individual dislocations in materials with high defect concentrations.
• The technique is valuable for materials characterization and defect analysis in single crystals.