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Structure and method for forming a thick bottom dielectric (TBD) for trench-gate devices

  • US 7,807,576 B2
  • Filed: 06/20/2008
  • Issued: 10/05/2010
  • Est. Priority Date: 06/20/2008
  • Status: Active Grant
First Claim
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1. A method of forming a semiconductor structure which includes a trench gate FET, comprising:

  • forming a hard mask over a surface of a semiconductor region, the hard mask including;

    (i) a first insulating layer over the surface of the semiconductor region, (ii) a first oxidation barrier layer over the first insulating layer, and (iii) a second insulating layer over the first oxidation barrier layer;

    forming a plurality of trenches in the semiconductor region using the hard mask; and

    forming a thick bottom dielectric (TBD) along a bottom of each trench, the first oxidation barrier layer preventing formation of a dielectric layer along the surface of the semiconductor region during formation of the TBD.

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