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Trench MOSFET with shallow trench structures

  • US 20090315104A1
  • Filed: 04/23/2009
  • Published: 12/24/2009
  • Est. Priority Date: 06/20/2008
  • Status: Abandoned Application
First Claim
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1. A vertical semiconductor power MOS device comprising a plurality of semiconductor power cells with each cell comprising a trenched gate surrounded by a source region with first type conductivity encompassed in a body region with second type conductivity above a drain region disposed on a bottom surface of a low-resistivity substrate with first type conductivity, wherein said MOS cell further comprising:

  • an epitaxial layer with the first type conductivity is grown on the substrate;

    an on-resistance reduction doped region underneath said trenched gate bottom with the first type conductivity having doping concentration higher than said epitaxial layer;

    a first insulating layer serving as gate oxide lining the inner surface of openings for trench gates;

    a second insulating layer functioning as thick oxide interlayer covering top surface of the epitaxial layer;

    a source-body contact trench opened through said thick oxide interlayer and said source region, and extending into said body region;

    a gate contact trench opened through said thick oxide interlayer and extending into trench-filling material in said trenched gate underneath metal gate runner, which is near termination served as metal field plate over said body region and said epitaxial region;

    a tungsten plug filled into said source-body contact trench and said gate contact trench, and padded with a barrier layer.a source metal layer and a gate metal layer formed over a resistance-reduction layer connected to said tungsten plug in said source-body contact trench and said gate contact trench, respectively;

    a drain metal layer formed on a bottom surface of the MOSFET.

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