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

4 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

Fingerprint

Ohmic contacts
Metallizing
Heterojunctions
electric contacts
CMOS
transistors
Metals
contact resistance
metal surfaces
roughness
Diffusion barriers
platforms
Contact resistance
Surface chemistry
fabrication
electrical resistivity
Surface morphology
Surface roughness
Semiconductor materials
Fabrication

All Science Journal Classification (ASJC) codes

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

Cite this

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title = "Microstructural characterization of Au-free Si/Ti/Al/Cu ohmic contacts in an AlGaN/GaN heterostructure",
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.",
author = "Seonno Yoon and Jangwon Bang and Yunwon Song and Jungwoo Oh",
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Microstructural characterization of Au-free Si/Ti/Al/Cu ohmic contacts in an AlGaN/GaN heterostructure. / Yoon, Seonno; Bang, Jangwon; Song, Yunwon; Oh, Jungwoo.

In: Thin Solid Films, Vol. 590, 01.09.2015, p. 335-339.

Research output: Contribution to journalArticle

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T1 - Microstructural characterization of Au-free Si/Ti/Al/Cu ohmic contacts in an AlGaN/GaN heterostructure

AU - Yoon, Seonno

AU - Bang, Jangwon

AU - Song, Yunwon

AU - Oh, Jungwoo

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AB - 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.

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