Enhancement of two-dimensional electron gas mobility using strain reduced AlGaN barriers grown by metalorganic vapor phase epitaxy under nitrogen atmosphere. (1st July 2022)

• Record Type: Journal Article
• Authors: Yamada, Atsushi; Yaita, Junya; Kotani, Junji
• Is Part Of: Japanese journal of applied physics. Volume 61:Number 7(2022)
• Publication Date: 2022-07-01
• Subjects: metalorganic vapor phase epitaxy -- III-nitride semiconductor materials -- high electron mobility transistors; Physics -- Periodicals; 621.05
• DOI: 10.35848/1347-4065/ac7624
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: We demonstrated high-electron-mobility transistors (HEMTs) with enhanced two-dimensional electron gas (2DEG) mobility using a low-strain AlGaN barrier grown by metalorganic vapor phase epitaxy under a nitrogen atmosphere. We investigated the effects of the growth temperature under a nitrogen atmosphere on the electrical properties of AlGaN-HEMT structures, focusing on 2DEG mobility. At growth temperatures below 855 °C, the 2DEG mobility decreased with decreasing growth temperature owing to an increase in the threading dislocation density. However, at growth temperatures above 855 °C, the 2DEG mobility decreased with increasing growth temperature. This finding was attributed to the compressive strain in the GaN channel, which increased with increasing growth temperature owing to the increased tensile strain in the AlGaN barriers. We concluded that temperatures around 855 °C are suitable for AlGaN barrier growth under nitrogen atmosphere. Finally, we achieved the highest 2DEG mobility of 2182 cm 2 V −1 s −1 with a low sheet resistance of 406 Ω sq −1 . using an Al0.41 Ga0.59 N barrier.