Structural characterization of V/Al/V/Au Ohmic contacts to n-type Al0.4Ga0.6N

• Published in: Chinese physics B Vol. 20; no. 4; pp. 369 - 373
• Main Author: 李涛 秦志新 许正昱 沈波 张国义
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.04.2011
• Subjects: 欧姆接触; 氮化铝; 温度依赖性; 结构表征; 透射电子显微镜分析
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/20/4/046101

This paper investigates the temperature dependence of the specific resistance in annealed V/Al/V/Au （15 nm/85 nm/20 nm/95 nm） contacts on n-A10.4Ga0.6N. Contacts annealed at 700 ℃ and higher temperatures show Ohmic behaviour. Annealing at 800 ℃ produces the lowest contact resistance. Samples annealed at 800 ℃have been analysed by using cross-sectional transmission electron microscopy and an energy dispersive x-ray spectrum. Limited reaction depths are observed between V-based contacts and n-AlGaN. The VN grains are found to form in the contact layer of the annealed samples, which can be considered as the key to the successful formation of Ohmic contact. The contact layer adjacent to AlGaN material consists of V Al-Au-N, AlN and AlAu alloys.