Low defect large area semi-polar (11[Formula: see text]2) GaN grown on patterned (113) silicon

Area of Science:

• Materials Science
• Semiconductor Growth
• Crystal Engineering

Background:

• Semi-polar Gallium Nitride (GaN) growth is crucial for optoelectronic devices.
• Patterned substrates offer a route to overcome challenges in GaN epitaxy.
• Silicon (Si) substrates are cost-effective alternatives to traditional sapphire.

Purpose of the Study:

• To investigate the growth of semi-polar GaN (11-22) templates on patterned Si (113) substrates.
• To analyze the structural properties and defect densities of the grown GaN layers.
• To compare the obtained results with those on patterned sapphire.

Main Methods:

• Patterning of Si (113) substrates using potassium hydroxide (KOH) etching.
• Deposition of Aluminum Nitride (AlN) and Aluminum Gallium Nitride (AlGaN) interlayers.
• Growth of Gallium Nitride (GaN) layers via epitaxy.
• Characterization using Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD).

Main Results:

• Achieved crack-free semi-polar GaN layers up to 5 µm thick.
• Dislocation propagation was managed by overgrowth, with densities below 10^6 cm⁻².
• Stacking fault densities were below 100 cm⁻².
• X-ray Full Width at Half Maximum (FWHM) values were 500" for (00.6) and 450" for (11.2) reflections.
• Surface roughness was highly variable and dependent on sidewall coalescence.

Conclusions:

• Semi-polar GaN templates can be successfully grown on patterned Si (113) substrates.
• The growth method demonstrates effective dislocation management.
• The quality achieved is comparable to that on patterned r-plane sapphire, with potential for further improvement.