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Trench mosfet with integrated schottky rectifier in same cell

  • US 20120037983A1
  • Filed: 08/10/2010
  • Published: 02/16/2012
  • Est. Priority Date: 08/10/2010
  • Status: Abandoned Application
First Claim
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1. A semiconductor power device comprising a plurality of trenched gates surrounded by source regions of a first conductivity type encompassed in body regions of a second conductivity type opposite to said first conductivity type in active area, said semiconductor power device further comprising:

  • a substrate of said first conductivity type;

    an epitaxial layer of said first conductivity type encompassing said body regions and said source regions supported on said substrate, having a lower doping concentration than said substrate;

    said trenched gates formed within said epitaxial layer further having a first gate oxide layer in lower portion of said trenched gates and having a second gate oxide layer in upper portion of said trenched gates, wherein said first gate oxide layer is thicker than said second gate oxide layer;

    a plurality of tilt-angle implanted drift regions of said first conductivity type formed in mesa area between every two adjacent said trenched gates encompassed in said epitaxial layer below said body region and having a higher doping concentration than said epitaxial layer;

    a plurality of trenched source-body-Schottky contacts penetrating through an insulation layer covering top surface of said epitaxial layer, further extending through said source regions and said body regions and into said tilt-angle implanted drift regions in said active area wherein trench bottom and lower portion trench sidewalls of said trenched source-body-Schottky contacts below said body regions covered with a Schottky barrier layer to function as an integrated Schottky rectifier;

    a plurality of ohmic contact doped regions of said second conductivity type surrounding sidewalls of said trenched source-body-Schottky contacts below said source regions, above said integrated Schottky rectifier, and having a higher doping concentration than said body regions.

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