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Roughened polysilicon surface capacitor electrode plate for high denity dram

  • US 5,110,752 A
  • Filed: 07/10/1991
  • Issued: 05/05/1992
  • Est. Priority Date: 07/10/1991
  • Status: Expired due to Term
First Claim
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1. A method to produce a roughened surface capacitor fabricated on a monocrystalline semiconductor substrate comprising:

  • depositing a thin first polycrystalline silicon layer to form a first capacitor plate on a particularly completed DRAM over a base insulating layer and a contact opening exposing said substrate;

    doping said first polycrystalline silicon layer with an impurity for semiconductors;

    depositing a thin layer of a metal capable of forming a silicide over the surface of said first layer;

    heating the resultant composite layer at a temperature to cause silicidation for a time sufficient to preferentially react with grains versus grain boundaries and to grow silicon grain crystals on the surfaces to thereby producing a roughened surface;

    removing the metal silicide from the resultant roughened composite layer with a suitable etchant;

    depositing a thin insulating layer to form a capacitor dielectric layer over the surface of the roughened layer; and

    depositing a second thin polycrystalline silicon layer over said thin insulating layer to form the second capacitor plate.

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