Performance comparison of Pt/Au and Ni/Au Schottky contacts on AlxGa1-x N/GaN heterostructures at high temperatures

• Published in: Chinese physics B Vol. 19; no. 12; pp. 478 - 483
• Main Author: 林芳 沈波 卢励吾 马楠 许福军 苗振林 宋杰 刘新宇 魏珂 黄俊
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.12.2010
• Subjects: 二维电子气; 异质结构; 性能比较; 氮化镓; 热退火效应; 肖特基接触; 高温退火
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/19/12/127304

In contrast with Au/Ni/Al0.25Ga0.75N/GaN Schottky contacts, this paper systematically investigates the effect of thermal annealing of Au/Pt/Alo.25Ga0.75N/GaN structures on electrical properties of the two-dimensional electron gas in Alo.25Ga0.75N/CaN heterostructures by means of temperature-dependent Hall and temperature-dependent current-voltage measurements. The two-dimensional electron gas density of the samples with Pt cap layer increases after annealing in N2 ambience at 600℃ while the annealing treatment has little effect on the two-dimensional electron gas mobility in comparison with the samples with Ni cap layer. The experimental results indicate that the Au/Pt/Al0.25Ga0.75N/GaN Schottky contacts reduce the reverse leakage current density at high annealing temperatures of 400-600 ℃. As a conclusion, the better thermal stability of the Au/Pt/Alo.25Gao.75N/GaN Schottky contacts than the Au/Ni/Al0.25Ga0.75N/GaN Schottky contacts at high temperatures can be attributed to the inertness of the interface between Pt and AlxGa1-xN.