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Method of making a power switching trench MOSFET having aligned source regions

  • US 5,897,343 A
  • Filed: 03/30/1998
  • Issued: 04/27/1999
  • Est. Priority Date: 03/30/1998
  • Status: Expired due to Term
First Claim
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1. A method of forming a semiconductor device, comprising the steps of:

  • providing a first semiconductor region of a first conductivity type;

    providing a patterned oxide layer over the first semiconductor region;

    forming a second semiconductor region of a second conductivity type in the first semiconductor region and aligned to an opening in the patterned oxide layer;

    forming a first insulating layer aligned to the opening in the patterned oxide layer;

    centering a trench within the second semiconductor region, wherein the trench extends from a surface of the second semiconductor region through the first and second semiconductor regions and the trench is aligned to the first insulating layer;

    filling the trench with a conductive material;

    covering the conductive material with a second insulating layer;

    removing the oxide layer to expose an edge of the first insulating layer; and

    aligning an implant layer to the edge of the first insulating layer, where the implant layer is disposed in the first semiconductor region adjacent to the second semiconductor region.

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