Microstructural characterization of Au-free Si/Ti/Al/Cu ohmic contacts in an AlGaN/GaN heterostructure

Seonno Yoon, Jangwon Bang, Yunwon Song, Jungwoo Oh

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

A complementary metal-oxide semiconductor (CMOS)-compatible Au-free Si/Ti/Al/Cu ohmic metallization scheme has been developed for AlGaN/GaN power transistors epitaxially grown on Si substrates. The Si/Ti/Al/Cu metallization exhibited a low specific contact resistance of 3.5 × 10- 6 ω cm2 after optimizing the Si interface layer. The ohmic metal surface was smooth with a root-mean-square roughness of 24 nm. Physical characterization confirmed that Cu diffusion into the semiconductor was suppressed because locally segregated TiSix alloys acted as a barrier. Shallow interfacial reactions of localized TiN alloys occurred in the AlGaN/GaN heterostructure. Without a designated diffusion barrier as in conventional Au-based metallization, the contact resistivity and surface morphology in Si/Ti/Al/Cu improved significantly, which helps address critical challenges associated with the fabrication of AlGaN/GaN power transistors on a Si CMOS platform.

Original languageEnglish
Pages (from-to)335-339
Number of pages5
JournalThin Solid Films
Volume590
DOIs
Publication statusPublished - 2015 Sep 1

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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