Fundamental Studies on Crystallization and Reaching the Equilibrium Shape in Basic Ammonothermal Method: Growth on a...

Area of Science:

• Materials Science
• Crystal Growth
• Semiconductor Physics

Background:

• Gallium Nitride (GaN) is a key semiconductor material.
• Ammonothermal growth is a primary method for producing high-quality GaN crystals.
• Understanding growth mechanisms is crucial for optimizing GaN production.

Purpose of the Study:

• Investigate the fundamental ammonothermal growth process of GaN.
• Determine the role of crystallographic planes during growth.
• Analyze the relationship between growth rates and seed off-cut angles.

Main Methods:

• Crystallization analysis on a lenticular GaN seed with varying off-cut.
• Examination of non-polar (12-10, 1-100) and basal (0001) plane slices.
• Selective etching to reveal growth features.
• Characterization using optical microscopy, X-ray topography, high-resolution X-ray diffraction, and secondary ion mass spectrometry.

Main Results:

• Identified key crystallographic planes governing GaN ammonothermal growth.
• Established relationships between growth rates along different crystallographic directions.
• Demonstrated the significant influence of seed off-cut on the growth process.
• Developed a growth model for ammonothermal GaN on a lenticular seed.

Conclusions:

• The study provides fundamental insights into ammonothermal GaN crystal growth.
• Findings are critical for optimizing GaN crystal quality and production.
• The developed growth model aids in understanding and controlling the process.