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Method for fabricating capacitor with high aspect ratio

  • US 8,962,437 B2
  • Filed: 06/12/2012
  • Issued: 02/24/2015
  • Est. Priority Date: 03/19/2012
  • Status: Active Grant
First Claim
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1. A method for fabricating a capacitor, comprising:

  • forming an etch stop layer over a semiconductor substrate having a storage node contact plug formed therein;

    forming a first silicon layer over the etch stop layer, wherein the first silicon layer is doped with a dopant;

    forming an undoped second silicon layer over the first silicon layer;

    forming an opening by etching the second silicon layer and the first silicon layer;

    forming a silicon oxide layer on sidewalls of the opening by oxidizing the first silicon layer and the second silicon layer;

    expanding the opening by removing the silicon oxide layer;

    etching the etch stop layer under the expanded opening;

    forming a storage node in the expanded opening; and

    removing the first silicon layer and the second silicon layer,wherein the first and second silicon layers comprise amorphous silicon and are heat-treated during a subsequent process.

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