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Method of fabricating a trench gate MOSFET for maximizing breakdown voltage

  • US 7,851,300 B2
  • Filed: 12/28/2008
  • Issued: 12/14/2010
  • Est. Priority Date: 12/28/2007
  • Status: Active Grant
First Claim
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1. A method comprising:

  • forming a second conductive type first epitaxial layer and a second conductive type second epitaxial layer over a first conductive type semiconductor substrate; and

    thenforming a first conductive type body region over the second conductive type second epitaxial layer; and

    theninjecting first conductive type impurities in the first conductive type body region in order that a bottom area thereof has a circular cross-section; and

    thenforming a plurality of trenches spaced apart in the first conductive body region; and

    thenforming a gate oxide layer in a respective one of the trenches; and

    thenforming a gate in a respective one of the trenches; and

    thenforming second conductive type emitter regions in the first conductive type body region; and

    thenforming a contact hole at the upper surface of the first conductive type body region between adjacent ones of the second conductive type emitter regions,wherein the first conductive type body region between the bottom area of the contact hole and the second conductive type second epitaxial layer is formed to maintain a predetermined thickness.

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