Study of GaN-Based Thermal Decomposition in Hydrogen Atmospheres for Substrate-Reclamation Processing

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Gallium nitride (GaN) is a critical semiconductor material.
• Patterned sapphire substrates (PSS) are used to improve GaN epitaxy.
• Understanding GaN thermal stability is essential for device fabrication and reliability.

Purpose of the Study:

• To investigate the thermal decomposition behavior of GaN-epilayers on PSS.
• To determine the influence of hydrogen flow rate on decomposition.
• To characterize the resulting nanostructures.

Main Methods:

• Thermal decomposition in a quartz furnace tube under hydrogen atmosphere.
• Controlled variation of hydrogen flow rates at 1200 °C.
• Transmission electron microscopy (TEM) for nanostructure analysis.

Main Results:

• GaN-based epilayers on PSS undergo thermal decomposition at 1200 °C.
• Complete removal of GaN was achieved.
• Gallium oxyhydroxide (GaO₂H) nanostructures were formed.
• GaO₂H nanostructures consist of 2-5 nm nanograins.
• Hydrogen flow rate was found to influence the decomposition reaction.

Conclusions:

• The thermal decomposition of GaN-epi/PSS in hydrogen yields GaO₂H nanostructures.
• Hydrogen flow rate is a critical parameter controlling the decomposition process.
• Detailed characterization of GaO₂H nanostructures provides insights into their formation.