Simultaneous formation of ohmic contacts for both N- and P-type 4H-SiC using NiAl-based contact materials

Susumu Tsukimoto, Toshitake Onishi, Kazuhiro Ito, Masanori Murakami

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    2 Citations (Scopus)

    Abstract

    In order to simplify a fabrication process of silicon carbide power MOSFETs (metal oxide semiconductor field effect transistors), development of a simultaneous formation process of ohmic contacts to both the p-well and n-source regions of the SiC devices using same contact materials and one step annealing was challenged. We succeeded to develop NiAl-based contact materials which provided ohmic behaviors for both n- and p-type 4H-SiC after one step annealing. The Ni/Al and Ni/Ti/Al ohmic contacts were prepared by depositing sequentially Ni, (Ti) and Al layers with various layer thicknesses onto the n- and p-type SiC substrates which were doped with N at 1×1019 cm-3 and with Al at 8×1018 cm-3, respectively. The Ni(50 nm)/Al(5 ∼ 6 nm) contacts showed ohmic behaviors for both the n- and p-type SiC substrates after annealing at 1000°C. The Ni(20 nm)/Ti(50 nm)/Al(50 ∼ 70 nm) contacts showed ohmic behaviors for both the n- and p-type SiC substrates after annealing at a lower temperature of 800°C. The specific contact resistances of these contacts were measured to be in the order of 10-3 Ω-cm2 for both p- and n-type SiC, and were found to have strong dependence of the Al layer thicknesses of materials. The interfacial microstructures of the NiAl-based contacts were also observed by transmission electron microscopy (TEM) to understand the current transport mechanism through the metal/SiC interfaces.

    Original languageEnglish
    Title of host publicationSilicon Carbide 2006 - Materials, Processing and Devices
    PublisherMaterials Research Society
    Pages359-364
    Number of pages6
    ISBN (Print)1558998721, 9781558998728
    DOIs
    Publication statusPublished - 2006
    Event2006 MRS Spring Meeting - San Francisco, CA, United States
    Duration: 2006 Apr 182006 Apr 20

    Publication series

    NameMaterials Research Society Symposium Proceedings
    Volume911
    ISSN (Print)0272-9172

    Other

    Other2006 MRS Spring Meeting
    CountryUnited States
    CitySan Francisco, CA
    Period06/4/1806/4/20

    ASJC Scopus subject areas

    • Materials Science(all)
    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering

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