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

Seonno Yoon; Jangwon Bang; Yunwon Song; Jungwoo Oh

doi:10.1016/j.tsf.2015.02.065

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

Seonno Yoon, Jangwon Bang, Yunwon Song, Jungwoo Oh

School of Integrated Technology

Research output: Contribution to journal › Article › peer-review

6 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 TiSi_x 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 language	English
Pages (from-to)	335-339
Number of pages	5
Journal	Thin Solid Films
Volume	590
DOIs	https://doi.org/10.1016/j.tsf.2015.02.065
Publication status	Published - 2015 Sept 1

Bibliographical note

Funding Information:
This work was partly supported by the IT R&D program of MOTIE/KEIT ( 10048931 , “The Development of Epi-growth Analysis for Next Generation Semiconductor and Power Semiconductor Fundamental Technology”); the Future Semiconductor Device Technology Development Program ( 10044735 , 10048536 ) funded by MOTIE and KSRC ; and MSIP , Korea, under the “IT Consilience Creative Program” ( NIPA-2014-H0201-14-1001 ) supervised by NIPA.

Publisher Copyright:
© 2015 Elsevier B.V.

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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10.1016/j.tsf.2015.02.065

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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",

note = "Funding Information: This work was partly supported by the IT R&D program of MOTIE/KEIT ( 10048931 , “The Development of Epi-growth Analysis for Next Generation Semiconductor and Power Semiconductor Fundamental Technology”); the Future Semiconductor Device Technology Development Program ( 10044735 , 10048536 ) funded by MOTIE and KSRC ; and MSIP , Korea, under the “IT Consilience Creative Program” ( NIPA-2014-H0201-14-1001 ) supervised by NIPA. Publisher Copyright: {\textcopyright} 2015 Elsevier B.V.",

year = "2015",

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doi = "10.1016/j.tsf.2015.02.065",

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AU - Yoon, Seonno

AU - Bang, Jangwon

AU - Song, Yunwon

AU - Oh, Jungwoo

N1 - Funding Information: This work was partly supported by the IT R&D program of MOTIE/KEIT ( 10048931 , “The Development of Epi-growth Analysis for Next Generation Semiconductor and Power Semiconductor Fundamental Technology”); the Future Semiconductor Device Technology Development Program ( 10044735 , 10048536 ) funded by MOTIE and KSRC ; and MSIP , Korea, under the “IT Consilience Creative Program” ( NIPA-2014-H0201-14-1001 ) supervised by NIPA. Publisher Copyright: © 2015 Elsevier B.V.

PY - 2015/9/1

Y1 - 2015/9/1

N2 - 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.

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

Abstract

Bibliographical note

All Science Journal Classification (ASJC) codes

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