Roughened polysilicon surface capacitor electrode plate for high denity dram
First Claim
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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Accused Products
Abstract
A method of fabricating a microminaturized capacitor having an electrode that is roughened to increase the effective area per unit area and resulting structure, particularly adapted for use in high density dynamic random access memory devices. The method involves depositing a conductive polycrystalline silicon layer. The depositing a metal such as a refractory metal over the polysilicon layer. The composite layer is heated to form a metal silicide and roughened polycrystalline silicon surface while the grains also grow large. The metal silicide is removed, leaving a roughened surface. The capacitor dielectric layer is deposited upon the roughened surface. The second conductive polycrystalline silicon layer is now formed upon said dielectric layer to complete the capacitor.
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Citations
17 Claims
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1. A method to produce a roughened surface capacitor fabricated on a monocrystalline semiconductor substrate comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification