Compliant Micron-Sized Patterned InGaN Pseudo-Substrates Utilizing Porous GaN.

Area of Science:

• Materials Science
• Solid State Physics
• Semiconductor Engineering

Background:

• Indium Gallium Nitride (InGaN) is a critical material for optoelectronic and electronic devices.
• Growing high-quality InGaN layers often faces challenges due to strain and lattice mismatch.
• Porous semiconductor layers offer potential for strain management and novel device architectures.

Purpose of the Study:

• To demonstrate the compliant behavior of patterned InGaN layers on porous GaN.
• To investigate the elastic relaxation mechanisms in InGaN-on-porous GaN structures.
• To explore methods for improving InGaN surface morphology for pseudo-substrate fabrication.

Main Methods:

• Growth of patterned InGaN layers on porous GaN substrates.
• Elastic relaxation analysis enabled by the low stiffness of porous GaN.
• High-resolution X-ray diffraction (HRXRD) for lattice constant and relaxation measurements.
• Metal-organic chemical vapor deposition (MOCVD) for InGaN growth and surface morphology optimization.

Main Results:

• Demonstrated compliant behavior and elastic relaxation of InGaN layers on porous GaN.
• Observed partial relaxation of regrown InGaN layers and increased relaxation of the pseudo-substrate.
• Achieved an improved surface morphology for InGaN layers.
• Attained the largest demonstrated a-lattice constant of 3.209 Å, indicating a fully relaxed InGaN film (Indium composition of 0.056).

Conclusions:

• Porous GaN effectively facilitates elastic relaxation in overlying InGaN layers.
• InGaN-on-porous GaN structures serve as viable pseudo-substrates for relaxed InGaN growth.
• Optimized MOCVD methods enhance surface morphology, paving the way for advanced device fabrication.