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

• Main Authors: Huan-Chung Wang, Ting-En Hsieh, Yueh-Chin Lin, Quang Ho Luc, Shih-Chien Liu, Chia-Hsun Wu, Chang Fu Dee, Burhanuddin Yeop Majlis, Edward Yi Chang
• Format: Article
• Language: English
• Published: IEEE 2018-01-01
• Series: IEEE Journal of the Electron Devices Society
• Subjects: AlGaN/GaN; MIS-HEMT; Al₂O₃; PEALD; oxygen plasma
• Online Access: https://ieeexplore.ieee.org/document/8125685/

We demonstrate the electrical performances of AlGaN/GaN metal-insulator-semiconductor-high electron mobility transistors (MIS-HEMTs) with high quality Al₂O₃ gate dielectric deposited by plasma enhanced atomic layer deposition using both H₂O and remote O₂ plasma as oxygen sources. Excellent gate-dielectric/GaN interface and Al₂O₃ 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 O₂ plasma in the ALD-Al₂O₃ deposition process is an effective and simple way to provide high quality gate dielectric for the GaN MIS-HEMTs production.