Correlation between the electrical properties and the interfacial microstructures of TiAl-based ohmic contacts to p-type 4H-SiC

S. Tsukimoto, K. Nitta, T. Sakai, M. Moriyama, Masanori Murakami

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    49 Citations (Scopus)

    Abstract

    In order to understand a mechanism of TiAl-based ohmic contact formation for p-type 4H-SiC, the electrical properties and microstructures of Ti/Al and Ni/Ti/Al contacts, which provided the specific contact resistances of approximately 2×10-5 Ω-cm2 and 7×10 -5 Ω-cm2 after annealing at 1000°C and 800°C, respectively, were investigated using x-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Ternary Ti 3SiC2 carbide layers were observed to grow on the SiC surfaces in both the Ti/Al and the Ni/Ti/Al contacts when the contacts yielded low resistance. The Ti3SiC2 carbide layers with hexagonal structures had an epitaxial orientation relationship with the 4H-SiC substrates. The (0001)-oriented terraces were observed periodically at the interfaces between the carbide layers and the SiC, and the terraces were atomically flat. We believed the Ti3SiC2 carbide layers primarily reduced the high Schottky barrier height at the contact metal/p-SiC interface down to about 0.3 eV, and, thus, low contact resistances were obtained for p-type TiAl-based ohmic contacts.

    Original languageEnglish
    Pages (from-to)460-466
    Number of pages7
    JournalJournal of Electronic Materials
    Volume33
    Issue number5
    DOIs
    Publication statusPublished - 2004 May

    Keywords

    • Microstructure
    • Ohmic contact
    • P-type 4H-SiC
    • Ti SiC
    • TiAl-based

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Electrical and Electronic Engineering
    • Materials Chemistry

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