Study of p-GaN Gate MOS-HEMT with Al2O3 Insulator for High-Power Applications

In this work, an enhancement-mode (E-mode) p-GaN gate metal-oxide-semiconductor high-electron-mobility transistor (MOS-HEMT) with 10-nm-thick Al2O3 film was successfully fabricated. Good oxide film quality and excellent Al2O3/p-GaN MOS interface properties were achieved, as evidenced by the C-V curves and hysteresis effect of Al2O3/p-GaN metal-oxide-semiconductor capacitors (MOSCAPs). Compared to the p-GaN gate, the HEMT exhibited threshold voltage (V-th) of 1.5 V and maximum drain current (I-D,I-max) of 189 mA/mm, the p-GaN gate MOS-HEMT with dielectric oxide Al2O3 exhibited higher threshold voltage of 2.1 V, and comparable maximum drain current of 217 mA/mm. In addition, owing to the high-energy bandgap and high breakdown field of Al2O3, the p-GaN gate MOS-HEMT demonstrated lower gate leakage current and higher breakdown voltage. The results indicated that p-GaN gate MOS-HEMT with Al2O3 gate insulator was promising for high-power application.

Automated summary

In this study, an enhancement-mode p-GaN MOS-HEMT with a 10-nm-thick Al2O3 film was fabricated successfully. The Al2O3 film exhibited good quality and the Al2O3/p-GaN MOS interface showed excellent properties. Compared to a p-GaN gate, the HEMT with Al2O3 gate insulator showed higher threshold voltage of 2.1 V and comparable maximum drain current of 217 mA/mm. Additionally, the p-GaN gate MOS-HEMT with Al2O3 demonstrated lower gate leakage current and higher breakdown voltage, thanks to the high-energy bandgap and high breakdown field of Al2O3. These findings suggest the promising application of p-GaN gate MOS-HEMT with Al2O3 gate insulator in high-power devices.