Investigation of Normally-Off p-GaN/AlGaN/GaN HEMTs Using a Self-Terminating Etching Technique with Multi-Finger...

Area of Science:

• Materials Science
• Semiconductor Physics
• Electrical Engineering

Background:

• Gallium nitride (GaN) high electron mobility transistors (HEMTs) are crucial for power electronics.
• Developing normally-off (enhancement-mode) p-GaN HEMTs is essential for simplified circuit design and improved efficiency.
• Existing fabrication methods often struggle with precise control and can introduce surface damage.

Purpose of the Study:

• To fabricate normally-off p-GaN HEMTs using a self-terminating etching technique.
• To investigate the impact of device geometry (gate width, number of fingers) on output current density.
• To demonstrate a high-performance enhancement-mode p-GaN HEMT.

Main Methods:

• Fabrication of multi-finger p-GaN HEMT devices.
• Utilized a self-terminating etching technique with a Cl2/BCl3/SF6-mixed gas plasma.
• Varied gate widths and the number of fingers to study their effects on device performance.

Main Results:

• Successfully fabricated normally-off p-GaN HEMTs with accurate etching depth control and low plasma damage.
• Demonstrated that device geometry influences output current density.
• Achieved a high-performance enhancement-mode p-GaN HEMT with a 60 mm gate width, exhibiting a 2.2 V threshold voltage and 6.7 A drain current.

Conclusions:

• The self-terminating etching technique is effective for fabricating high-quality, normally-off p-GaN HEMTs.
• Device design parameters significantly impact current handling capabilities.
• The developed p-GaN HEMT shows promise for high-power and high-frequency applications.