Quantitative defect analysis in MOCVD GaN-on-GaN using cathodoluminescence.

Area of Science:

• Materials Science
• Semiconductor Physics
• Analytical Chemistry

Background:

• Metal-organic chemical vapor deposition (MOCVD) is crucial for GaN-on-GaN epitaxy.
• Understanding interfacial impurities is vital for optimizing GaN device performance.
• Quantitative characterization of these impurities remains a challenge.

Purpose of the Study:

• To establish cathodoluminescence (CL) as a quantitative method for probing impurities at GaN-on-GaN homoepitaxial interfaces.
• To develop an analytical model for determining impurity concentrations from CL intensity.
• To validate the CL-based model against established characterization techniques.

Main Methods:

• Utilizing cathodoluminescence (CL) as a quantitative characterization technique.
• Analyzing electron beam induced non-equilibrium carrier recombination mechanisms.
• Developing and applying an analytical model to extract impurity concentrations from CL intensity.
• Comparing CL-derived impurity data with capacitance-voltage (C-V) measurements.

Main Results:

• CL intensity contrast strongly correlates with interfacial impurity concentrations.
• An analytical model was successfully developed to quantitatively determine impurity levels from CL intensity.
• The impurity concentrations extracted using the CL model showed good agreement with C-V measurements.
• The study demonstrates the potential of CL for quantitative impurity analysis in GaN-on-GaN structures.

Conclusions:

• Cathodoluminescence is a viable quantitative technique for assessing impurities in MOCVD-grown GaN-on-GaN interfaces.
• The proposed analytical model provides accurate impurity quantification, corroborated by C-V measurements.
• This CL-based approach offers a powerful tool for material characterization and can be extended to other material systems.