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US 7,459,758 B2Granted
Transistor structure and method for making same
AssigneeSTMicroelectronics S.r.l.
InventorFrank Randolph Bryant
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Abstract
A gate structure in a transistor and method for fabricating the structure. A gate structure is formed on a substrate. The gate structure includes three layers: an oxide layer, a nitride layer and a polysilicon layer. The oxide layer is located on the substrate, the nitride layer is located on the oxide layer, and the polysilicon layer is located on the nitride layer. The gate structure is reoxidized to form a layer of oxide over the gate structure.
Claims11
An integrated circuit device comprising:
- a substrate;
- a gate structure, wherein the gate structure includes:
- a gate oxide layer on the substrate,
- a nitride layer on and directly contacting the gate oxide layer, and
- a polysilicon layer over to nitride layer;
- a channel region under the gate structure;
- and
- source/drain regions in the substrate adjacent the channel region,
- wherein the gate structure has a peripheral edge and further including an uplift in portions of the nitride layer proximate the peripheral edge of the gate structure, the uplift caused during reoxidation of the polysilicon layer within the gate structure, wherein asperities that increase an electric field at the peripheral edge during operation are absent from a bottom surface of the polysilicon layer and a thickness of an oxidation layer produced by said reoxidation is from about 25 Å to about 500 Å on said substrate.
6 more elements
Dependencies are inferred from the claim text.