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Super-junction trench MOSFET with resurf step oxide and the method to make the same

  • US 8,067,800 B2
  • Filed: 12/28/2009
  • Issued: 11/29/2011
  • Est. Priority Date: 12/28/2009
  • Status: Active Grant
First Claim
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1. A super-junction trench MOSFET with resurf stepped oxide, comprising:

  • a substrate of a first conductivity type;

    an epitaxial layer of said first conductivity type grown on said substrate, said epitaxial layer having a lower doping concentration than said substrate;

    a plurality of trenches starting from the upper surface of said epitaxial layer and down extending into said epitaxial layer;

    a first insulation layer along the inner surface of lower portion of each of said trenches;

    a plurality of source electrodes within lower portion of said trenches and surrounded with said first insulation layer;

    a second insulation layer along the inner surface of upper portion of each of said trenches and along the top surface of said first insulation layer and said source electrodes, said second insulation layer has a thinner thickness than said first insulation layer;

    a plurality of gate electrodes within upper portion of said trenches and surrounded with said second insulation layer;

    a plurality of first doped column regions of said first conductivity type with column shape within said epitaxial layer, each of said first doped column regions formed adjacent to the sidewalls of said trenches and having column bottom above trench bottom of said trenches;

    a plurality of second doped column regions of a second conductivity type with column shape within said epitaxial layer, each of said second doped column regions formed in parallel surrounded with said first doped column regions;

    a plurality of body regions of said second conductivity type within said epitaxial layer, each of said body regions formed adjacent to the upper sidewalls of said trenches and onto the top surface of said first doped column regions and said second doped column regions; and

    a plurality of source regions of said first conductivity type near the top surface of said body region and adjacent to the upper sidewalls of said trenches, said source region has a higher doping concentration than said epitaxial layer.

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