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

Seonno Yoon, Jangwon Bang, Yunwon Song, Jungwoo Oh

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6 Citations (Scopus)


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
Publication statusPublished - 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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