Low resistance copper-based ohmic contact for AlGaN/GaN high electron mobility transistors

Yuen Yee Wong, Yu Kong Chen, Jer Shen Maa, Hung Wei Yu, Yung Yi Tu, Chang Fu Dee, Chi Chin Yap, Edward Yi Chang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Ti/Al/Ni/Cu ohmic contact for AlGaN/GaN structure has been fabricated. The Ni layer played an important role in achieving low specific contact resistance (rc), smooth morphology, and excellent edge acuity. With a 50-Å Ni layer, a rc of 1.35 × 10-6 Ω-cm 2 and a root-mean-square roughness of 7.65 nm have been realized. The characterization results indicated that no evidence of Cu diffusion into the semiconductor layers. The formation of Al-Cu and Ti-Cu alloys might have confined the Cu within the ohmic metal. In the absence of gold, the surface roughening caused by Au-Al alloy in conventional Ti/Al/Ni/Au structure was also prevented.

Original languageEnglish
Article number152104
JournalApplied Physics Letters
Volume103
Issue number15
DOIs
StatePublished - 7 Oct 2013

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