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Trench MOSFET device with polycrystalline silicon source contact structure

  • US 20030107080A1
  • Filed: 11/20/2001
  • Published: 06/12/2003
  • Est. Priority Date: 11/20/2001
  • Status: Active Grant
First Claim
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1. A trench MOSFET transistor device comprising:

  • a silicon substrate of a first conductivity type;

    a silicon epitaxial layer of said first conductivity type over said substrate, said epitaxial layer having a lower majority carrier concentration than said substrate;

    a trench extending into said epitaxial layer from an upper surface of said epitaxial layer;

    an insulating layer lining at least a portion of said trench;

    a conductive region within said trench adjacent said insulating layer;

    a body region of a second conductivity type provided within an upper portion of said epitaxial layer and adjacent said trench;

    a source region of said first conductivity type provided within an upper portion of said body region and adjacent said trench;

    an upper region of second conductivity type within an upper portion of said body region and adjacent said source region, said upper region having a higher majority carrier concentration than said body region; and

    a source contact region disposed on said epitaxial layer upper surface, said source contact region comprising;

    (a) a doped polycrystalline silicon contact region in electrical contact with said source region and (b) a metal contact region adjacent said doped polycrystalline silicon contact region and in electrical contact with said source region and with said upper region.

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