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Approach to integrate Schottky in MOSFET

  • US 8,431,470 B2
  • Filed: 04/04/2011
  • Issued: 04/30/2013
  • Est. Priority Date: 04/04/2011
  • Status: Active Grant
First Claim
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1. A method for forming an integrated structure combining one or more field effect transistors and a Schottky diode on a lightly-doped semiconductor substrate composition, comprising:

  • a) forming a plurality of trenches formed into the substrate composition and extending into the substrate composition forming a plurality of mesas there between,b) substantially filling each trench with a conductive material that is separated from the trench walls by a thin layer of dielectric material to form a gate region of the one or more field effect transistors;

    c) forming two doped body regions of a first conductivity type opposite that of the substrate inside each mesa, each doped body region including a corresponding contact trench that extends along a portion of the depth of the substrate composition, whereby there are two contact trenches, the two doped body regions and their corresponding contact trenches being separated by an exposed portion of the substrate composition, wherein each contact trench has an end that abuts the exposed portion of the substrate composition;

    d) forming a pair of doped source regions of a second conductivity type inside each doped body region, the pair of doped source regions being positioned adjacent to and on opposite sides of each contact trench; and

    e) forming a Schottky diode comprising Schottky barrier metal inside each contact trench of the two doped body regions, the Schottky barrier metal forming a Schottky junction at an interface between the Schottky barrier metal and an exposed vertical sidewall of the exposed portion of the substrate composition separating the two doped body regions.

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