Structure for scalable, low-cost polysilicon dram in a planar capaacitor
AssigneeInternational Business Machines Corporation
InventorsJeffrey S. Brown, Randy W. Mann
Life of this patent
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Abstract
Capacitor structures that have increased capacitance without compromising cell area are provided as well as methods for fabricating the same. A first capacitor structure includes insulating material present in holes that are formed in a semiconductor substrate, where the insulating material is thicker on the bottom wall of each capacitor hole as compared to the sidewalls of each hole. In another capacitor structure, deep capacitor holes are provided that have an isolation implant region present beneath each hole.
Claims20
A structure formed on a substrate comprising:
- a plurality of isolation filled trenches in the substrate;
- a plurality of holes in the substrate, each having a plurality of sidewalls and a bottom wall, located in a region of a semiconductor substrate in which said plurality of isolation filled trenches are absent, said holes having a depth proximate that of said plurality of isolation filled trenches;
- insulating material present in each of said plurality of holes on said plurality of sidewalls and bottom wall;
- and
- a conductor overfilling each of said holes and extending onto an adjacent upper surface of the substrate.
A method of fabricating a capacitor structure comprising the steps of:
- forming a plurality of holes in a region of a semiconductor substrate, each hole having a plurality of sidewalls and a bottom wall;
- forming insulating material in each hole, wherein in first ones of said holes said insulating material completely fills said holes and in second ones of said holes said insulating material formed only on said plurality of sidewalls and said bottom wall;
- and
- overfilling each of said second ones of said hole with a conductor.
Dependencies are inferred from the claim text.