Microstructural evidence on electrical properties of Ta/Ti/Al and Ti/Ta/Al ohmic contacts to n-AlGaN/GaN

被引：42

作者：

Lim, SH

Washburn, J

Liliental-Weber, Z

Qiao, D

机构：

[1] Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA

[2] Univ Calif San Diego, La Jolla, CA 92093 USA

来源：

APPLIED PHYSICS LETTERS | 2001年 / 78卷 / 24期

关键词：

D O I：

10.1063/1.1378312

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Electrical properties and microstructures of Ta/Ti/Al and Ti/Ta/Al contacts to n-AlGaN/GaN heterostructure held-effect transistor structures were investigated using the transmission line method and transmission electron microscopy. The specific resistivity (5.3 X 10(-7) Ohm cm(2)) of Ta/Ti/Al contacts is much lower than that (5.1 X 10(-4) Ohm cm(2)) of Ti/Ta/Al contacts, for the same heterostructure and similar metallization. The contact resistivity was found to depend on the thickness of the AlGaN layer, interfacial phase, and interface roughness. The formation of interfacial phases by solid-state reactions with the metal layer during annealing appears to be essential for ohmic behavior on n-III-nitrides suggesting a tunneling contact mechanism. (C) 2001 American Institute of Physics.

引用

页码：3797 / 3799

页数：3

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