Design and Optimization of AlGaN/AlN/GaN L‑SBD for Radiofrequency Applications.

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Physics

Background:

• Lateral Schottky barrier diodes (L-SBDs) are crucial for high-frequency applications.
• Optimizing carrier confinement in AlGaN/GaN heterostructures is key to improving device performance.
• Existing L-SBDs face limitations in RF figures of merit due to carrier transport and interface properties.

Purpose of the Study:

• To investigate the impact of an AlN interlayer on the RF performance of AlGaN/GaN L-SBDs.
• To analyze how varying AlN interlayer thickness affects device characteristics.
• To enhance carrier confinement and RF metrics through interface engineering.

Main Methods:

• Fabrication and characterization of L-SBDs with AlN interlayers of varying thicknesses (1-3 nm).
• Electrical and dynamic behavior analysis, including current transport and capacitance measurements.
• Development and calibration of simulation models against experimental data to understand physical mechanisms.

Main Results:

• An optimized 3 nm AlN interlayer increased polarization-induced charge, enhancing carrier concentration and mobility.
• The optimized device demonstrated a 9% improvement in forward current (630 mA/mm).
• Significant improvements were observed in cutoff frequency (14.11% increase to 0.283 THz), dynamic conductance (10% enhancement to 310 mS/mm), and voltage sensitivity (90% improvement to 1180 mV/mW).

Conclusions:

• The AlN interlayer effectively enhances carrier confinement and mitigates alloy scattering.
• Optimized GaN-based L-SBDs with AlN interlayers show superior RF performance.
• These devices are highly promising for high-frequency detector and microwave mixer applications.