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Approach to integrate Schottky in MOSFET

  • US 8,828,857 B2
  • Filed: 04/29/2013
  • Issued: 09/09/2014
  • 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, the method comprising:

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

    b) forming at least two contact trenches in each mesa, each contact trench extending along a portion of depth of a doped body region of a first conductivity type opposite that of the substrate formed inside each mesa, whereby at least two contact trenches are separated by an exposed portion of the substrate, wherein each contact trench has an end that abuts the exposed portion of the substrate composition;

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

    d) forming a Schottky diode comprising Schottky barrier metal formed over the exposed portion of the substrate, the Schottky barrier metal forming a Schottky junction at an interface between the Schottky barrier metal and an exposed surface of the exposed portion of the substrate separating the two contact trenches.

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