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Method for producing a cell of a semiconductor memory

  • US 6,566,193 B2
  • Filed: 03/12/2002
  • Issued: 05/20/2003
  • Est. Priority Date: 03/12/2001
  • Status: Expired due to Term
First Claim
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1. A method of producing a memory cell of a semiconductor memory, which comprises the following steps:

  • providing a substrate;

    forming a first trench in the substrate;

    depositing a capacitor dielectric in the trench;

    depositing a conductive trench fill in the trench;

    sinking the conductive trench fill into the trench;

    depositing a first insulating layer on the conductive trench fill in the trench;

    overgrowing the first insulating layer epitaxially with an epitaxial layer, proceeding from the substrate;

    forming a second trench in the epitaxial layer, the second trench extending through the first insulating layer to the conductive trench fill, and thereby removing a part of the substrate to the conductive trench fill, and forming a ridge from the epitaxial layer;

    etching the first insulating layer, thereby undercutting the epitaxial layer;

    depositing and sinking a contact layer, whereby the contact layer remains in an undercut region beneath the epitaxial layer;

    depositing and sinking a second insulating layer in the second trench;

    forming a gate oxide at the ridge;

    forming lateral margin ridges as a gate on the gate oxide;

    incorporating dopant into the ridge, thereby forming a doped region;

    forming a bit line on the doped region;

    forming a word line over the bit line; and

    forming a word line contact for electrically connecting the gate to the word line.

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