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Non-Buffer Epi-AlGaN/GaN on SiC for High-Performance Depletion-Mode MIS-HEMTs Fabrication
Penghao Zhang1, Luyu Wang1, Kaiyue Zhu2
1State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China.
Micromachines
|August 26, 2023
Summary
A novel AlGaN/GaN epitaxial structure without a buffer layer shows improved crystalline quality and comparable transport properties. This design enables high-performance HEMTs with reduced electron trapping, crucial for power electronics.
Area of Science:
- Materials Science
- Semiconductor Physics
- Device Engineering
Background:
- Conventional AlGaN/GaN epitaxy on SiC and Si substrates often relies on thick buffer layers, impacting crystalline quality and device performance.
- Optimizing epitaxial growth for high-power electronics requires minimizing defects and enhancing carrier confinement.
Purpose of the Study:
- To investigate a novel AlGaN/GaN epitaxial structure grown directly on an AlN nucleation layer without a conventional buffer layer.
- To analyze the material properties, crystalline quality, and device performance of this non-buffer structure.
- To demonstrate the potential of this design for high-performance high-electron-mobility transistors (HEMTs).
Main Methods:
- Epitaxial growth of AlGaN/GaN on SiC substrate using a novel design without a thick buffer layer.
- Material characterization including crystalline quality and surface morphology analysis.
- Hall measurements to evaluate transport properties and carrier distribution.
- Fabrication and testing of depletion-mode Metal-Insulator-Semiconductor High-Electron-Mobility Transistors (MIS-HEMTs).
Main Results:
- The non-buffer AlGaN/GaN structure exhibited superior crystalline quality and surface morphology compared to conventional structures.
- Comparable transport properties were achieved without a buffer layer, attributed to effective two-dimensional electron gas (2DEG) confinement.
- High-performance depletion-mode MIS-HEMTs demonstrated low on-resistance (5.84 Ω·mm) and high output current (1002 mA/mm).
- Significantly reduced electron trapping was observed, evidenced by minimal saturation current decrease under high bias.
Conclusions:
- The novel non-buffer AlGaN/GaN epitaxy offers a promising alternative for high-quality material growth.
- This approach enables excellent 2DEG confinement and high-performance HEMT devices.
- The reduced electron trapping makes this structure highly suitable for demanding power electronics applications.
