Effect of Dual Al<sub>2</sub>O<sub>3</sub> MIS Gate Structure on DC and RF Characteristics of Enhancement-Mode GaN HEMT
A dual Al<sub>2</sub>O<sub>3</sub> MIS gate structure is proposed to enhance the DC and RF performance of enhancement-mode GaN high-electron mobility transistors (HEMTs). As a result, the proposed MOS-HEMT with a dual recessed MIS gate structure offers 84% improvements in cut...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-06-01
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| Series: | Micromachines |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2072-666X/16/6/687 |
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| Summary: | A dual Al<sub>2</sub>O<sub>3</sub> MIS gate structure is proposed to enhance the DC and RF performance of enhancement-mode GaN high-electron mobility transistors (HEMTs). As a result, the proposed MOS-HEMT with a dual recessed MIS gate structure offers 84% improvements in cutoff frequency (f<sub>T</sub>) and 92% improvements in maximum oscillation frequency (f<sub>max</sub>) compared to conventional HEMTs (from 7.1 GHz to 13.1 GHz and 17.5 GHz to 33.6 GHz, respectively). As for direct-current characteristics, a remarkable reduction in off-state gate leakage current and a 26% enhancement in the maximum saturation drain current (from 519 mA·mm<sup>−1</sup> to 658 A·mm<sup>−1</sup>) are manifested in HEMTs with new structures. The maximum transconductance (g<sub>m</sub>) is also raised from 209 mS·mm<sup>−1</sup> to 246 mS·mm<sup>−1</sup>. Correspondingly, almost unchanged gate–source capacitance curves and gate–drain capacitance curves are also discussed to explain the electrical characteristic mechanism. These results indicate the superiority of using a dual Al<sub>2</sub>O<sub>3</sub> MIS gate structure in GaN-based HEMTs to promote the RF and DC performance, providing a reference for further development in a miniwatt antenna amplifier and sub-6G frequencies of operation. |
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| ISSN: | 2072-666X |