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Buried strap contact for a storage capacitor and method for fabricating it

  • US 20050026359A1
  • Filed: 06/25/2004
  • Published: 02/03/2005
  • Est. Priority Date: 06/26/2003
  • Status: Active Grant
First Claim
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1. A method for fabricating a buried strap contact for a storage capacitor of a memory cell, the storage capacitor being formed in a trench of a semiconductor substrate with an outer electrode layer around a lower region of the trench in the semiconductor substrate, a dielectric intermediate layer embodied on the lower region of the trench wall of the trench, an insulation layer, which is formed in a manner adjoining the dielectric intermediate layer on an upper region of the trench wall of the trench, and an inner electrode layer essentially filling the trench, comprising:

  • etching back of the inner electrode layer into the trench;

    removing the uncovered insulator layer from the trench wall to define buried strap contact areas;

    depositing a liner layer to cover the inner electrode layer in the trench and the uncovered trench wall;

    forming a spacer layer with the material of the inner electrode layer on the liner layer at the trench wall;

    removing the uncovered liner layer from the inner electrode layer in the trench; and

    filling the trench with the material of the inner electrode layer.

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