Low-thermal-budget Au-free ohmic contact to an ultrathin barrier AlGaN/GaN heterostructure utilizing a micro-patterned ohmic recess

• 作者: Wen Shi Sen Huang Xinhua Wang Qimeng Jiang Yixu Yao Lan Bi Yuchen Li Kexin Deng Jie Fan Haibo Yin Ke Wei Yankui Li Jingyuan Shi Haojie Jiang Junfeng Li Xinyu Liu
• 来源期刊: 半导体学报（英文版）
• 年，卷（期）: 2021,（9）
• 所属期刊栏目: ARTICLES
• 页码范围: 51-55
• 页数: 5页
• 语种: 英文
• DOI: 10.1088/1674-4926/42/9/092801

摘要

A pre-ohmic micro-patterned recess process,is utilized to fabricate Ti/Al/Ti/TiN ohmic contact to an ultrathin-barrier(UTB) AlGaN/GaN heterostructure,featuring a significantly reduced ohmic contact resistivity of 0.56 Ω.mm at an alloy temperat-ure of 550 ℃.The sheet resistances increase with the temperature following a power law with the index of +2.58,while the spe-cific contact resistivity decreases with the temperature.The contact mechanism can be well described by thermionic field emis-sion (TFE).The extracted Schottky barrier height and electron concentration are 0.31 eV and 5.52 × 1018 cm-3,which suggests an intimate contact between ohmic metal and the UTB-AlGaN as well as GaN buffer.A good correlation between ohmic trans-fer length and the micro-pattern size is revealed,though in-depth investigation is needed.A preliminary CMOS-process-compat-ible metal-insulator-semiconductor high-mobility transistor (MIS-HEMT) was fabricated with the proposed Au-free ohmic con-tact technique.