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Buffer Traps Effect on GaN-on-Si High-Electron-Mobility Transistor at Different Substrate Voltages.
Yuan Lin1, Min-Lu Kao1, You-Chen Weng2
1Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Micromachines
|December 23, 2022
Summary
Investigating substrate voltage (VSUB) in Gallium Nitride on Silicon (GaN-on-Si) high electron mobility transistors (HEMTs) reveals its impact on device performance. Applying specific VSUB levels can enhance breakdown voltage and dynamic on-resistance by managing charge traps.
Area of Science:
- Materials Science
- Semiconductor Physics
- Electrical Engineering
Background:
- Gallium Nitride on Silicon (GaN-on-Si) high electron mobility transistors (HEMTs) are crucial for power applications.
- Substrate voltage (VSUB) influences the behavior of traps within the buffer stack and their effect on 2DEG conductivity.
- Understanding trap dynamics is essential for optimizing GaN-on-Si HEMT performance.
Purpose of the Study:
- To investigate the effects of substrate voltage (VSUB) on GaN-on-Si HEMTs with superlattice transition layers.
- To analyze how VSUB impacts 2DEG conductivity, buffer charge redistribution, and trap ionization.
- To determine the relationship between VSUB and key performance metrics like breakdown voltage (BV) and dynamic on-resistance (Ron).
Main Methods:
- Experimental investigation of GaN-on-Si HEMTs with superlattice transition layers.
- Application of varying substrate voltages (VSUB) to the devices.
- Analysis of 2-dimensional electron gas (2DEG) conductivity, charge redistribution, and trap behavior.
Main Results:
- Negative VSUB increases ionized donor and acceptor traps, enhancing breakdown voltage (BV) by improving vertical electric field distribution.
- Positive VSUB aids in refilling ionized traps, leading to a slight improvement in dynamic on-resistance (Ron) degradation.
- Asymmetric electron injection into the buffer stack layer is observed, influenced by VSUB.
Conclusions:
- Substrate voltage (VSUB) significantly modulates the electrical performance of GaN-on-Si HEMTs through field effect and buffer trapping.
- Optimizing VSUB is critical for enhancing breakdown voltage and dynamic on-resistance in power applications.
- The study highlights the complex interplay between VSUB, trap dynamics, and charge redistribution in GaN-on-Si HEMTs.
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