AlGaN/GaN MIS-HEMTs With High Quality ALD-Al2O3 Gate Dielectric Using Water and Remote Oxygen Plasma As Oxidants

We demonstrate the electrical performances of AlGaN/GaN metal-insulator-semiconductor-high electron mobility transistors (MIS-HEMTs) with high quality Al
₂
O
₃
gate dielectric deposited by plasma enhanced atomic layer deposition using both H
₂
O and remote O
₂
plasma as oxygen sources. Excellent gate-dielectric/GaN interface and Al
₂
O
₃
film quality were obtained, resulting in a very small threshold voltage hysteresis and a low interface trap density. The MIS-HEMT device exhibited high on/off current ratio of ~1010, steep subthreshold slope, small gate leakage current, low dynamic on-resistance degradation, and effectively current collapse suppression. These results indicate that incorporating remote O
₂
plasma in the ALD-Al
₂
O
₃
deposition process is an effective and simple way to provide high quality gate dielectric for the GaN MIS-HEMTs production.