Analysis of grain boundary dislocations by large angle convergent beam electron diffraction

Area of Science:

• Materials Science
• Solid State Physics
• Crystallography

Background:

• Grain boundaries in silicon significantly influence material properties.
• Analyzing dislocations within these boundaries is crucial for understanding material behavior.
• Existing methods for dislocation analysis at grain boundaries have limitations.

Purpose of the Study:

• To apply Large Angle Convergent Beam Electron Diffraction (LACBED) for analyzing secondary dislocations in sigma3 and sigma9 silicon grain boundaries.
• To demonstrate the effectiveness of LACBED in imaging and characterizing dislocations at grain boundaries.
• To identify boundary-specific dislocations and their Burgers vectors.

Main Methods:

• Utilizing Large Angle Convergent Beam Electron Diffraction (LACBED) on silicon samples with sigma3 and sigma9 grain boundaries.
• Selecting common crystal plane reflections to minimize boundary interference and highlight dislocations.
• Applying standard Cherns-Preston rules for dislocation image analysis.

Main Results:

• LACBED images of dislocations in grain boundaries are similar to those in single crystals.
• Sufficient common reflections were identified for complete dislocation analysis.
• Dislocations were confirmed to have integer g x b values, indicating Displacement Shift Complete (DSC) lattice vectors.
• Boundary-specific DSC dislocations were identified for both sigma3 and sigma9 boundaries.

Conclusions:

• LACBED is a viable technique for analyzing dislocations in silicon grain boundaries.
• The Burgers vectors of these dislocations are DSC lattice vectors.
• The methodology can be extended to analyze other coincidence boundaries in silicon.