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Operational Characteristics of AlGaN/GaN High-Electron-Mobility Transistors with Various Dielectric Passivation
Ji-Hun Kim1, Chae-Yun Lim1, Jae-Hun Lee1
1Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
Micromachines
|September 28, 2024
Summary
This study optimized AlGaN/GaN HEMTs using high-k passivation. HfO2 partial passivation improved frequency response and figure of merit, balancing breakdown voltage for high-power applications.
Area of Science:
- Materials Science
- Electrical Engineering
- Semiconductor Physics
Background:
- Aluminum Gallium Nitride/Gallium Nitride (AlGaN/GaN) high-electron-mobility transistors (HEMTs) are crucial for high-power and high-frequency electronics.
- Passivation layers significantly influence HEMT performance, affecting breakdown voltage and operational stability.
- Optimizing passivation is key to enhancing device capabilities for demanding applications.
Purpose of the Study:
- To investigate the impact of various passivation materials and structures on AlGaN/GaN HEMT operational characteristics.
- To explore the use of high-k dielectric materials like Al2O3 and HfO2 for improved breakdown voltage.
- To analyze hybrid and partial passivation structures to mitigate frequency reduction caused by parasitic capacitances.
Main Methods:
- Simulations calibrated with experimental data from a basic Si3N4 passivation structure.
- Replacement of Si3N4 with high-k materials (Al2O3, HfO2) to assess breakdown voltage improvements.
- Analysis of hybrid and partial passivation structures to evaluate trade-offs between breakdown voltage and cut-off frequency.
Main Results:
- Al2O3 and HfO2 passivation increased breakdown voltage by 6.62% and 17.45% respectively, compared to Si3N4.
- Increased parasitic capacitances with high-k materials led to reduced cut-off frequencies.
- HfO2 partial passivation showed a 7.6% decrease in breakdown voltage but an 82.76% increase in cut-off frequency compared to HfO2.
- The HfO2 partial passivation structure achieved the highest Johnson's figure of merit.
Conclusions:
- HfO2 partial passivation offers a promising balance between high breakdown voltage and enhanced frequency characteristics for AlGaN/GaN HEMTs.
- This optimized structure addresses the trade-offs inherent in high-k dielectric passivation.
- The HfO2 partial passivation structure is a strong candidate for future high-power, high-frequency device applications.
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