Gate feature in finFET device
First Claim
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1. A method for forming a fin field-effect transistor (FinFET), comprising:
- forming a fin structure protruding a major surface of a substrate;
exposing an upper portion of the fin structure by surrounding a lower portion of the fin structure;
forming a dummy poly layer over the upper portion of the fin structure;
etching an upper side portion of the dummy poly layer using a first etching process;
etching a lower side portion of the dummy poly layer using a second etching process thereby exposing an end portion of the upper portion of the fin and forming a poly footing feature that extends beyond a vertical sidewall of a remaining portion of the dummy poly layer;
forming a dielectric layer over the exposed end portion and along the vertical sidewall; and
removing the remaining portion of the dummy poly layer and the poly footing feature thereby forming a void to expose a central portion and a side portion of the upper portion of the fin structure, wherein the side portion extends beyond a vertical projection of the vertical sidewall.
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Abstract
A semiconductor device includes a fin structure, disposed on a substrate, that horizontally extends along a direction; and a gate feature comprising a gate dielectric layer and at least a first metal gate layer overlaying the gate dielectric layer, wherein the gate dielectric layer and the first metal gate layer traverse the fin structure to overlay a central portion of the fin structure and further extend along the direction to overlay at least a side portion of the fin structure that is located outside a vertical projection of a sidewall of the gate feature.
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Citations
20 Claims
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1. A method for forming a fin field-effect transistor (FinFET), comprising:
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forming a fin structure protruding a major surface of a substrate; exposing an upper portion of the fin structure by surrounding a lower portion of the fin structure; forming a dummy poly layer over the upper portion of the fin structure; etching an upper side portion of the dummy poly layer using a first etching process; etching a lower side portion of the dummy poly layer using a second etching process thereby exposing an end portion of the upper portion of the fin and forming a poly footing feature that extends beyond a vertical sidewall of a remaining portion of the dummy poly layer; forming a dielectric layer over the exposed end portion and along the vertical sidewall; and removing the remaining portion of the dummy poly layer and the poly footing feature thereby forming a void to expose a central portion and a side portion of the upper portion of the fin structure, wherein the side portion extends beyond a vertical projection of the vertical sidewall. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of making a semiconductor device, comprising:
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forming a fin structure on a substrate; and forming a gate feature over the fin structure, the gate feature comprising a gate dielectric layer and at least a first metal gate layer overlaying the gate dielectric layer, wherein the gate dielectric layer and the first metal gate layer traverse the fin structure to overlay a central portion of the fin structure and opposite side portions of the fin structure that are located in respective undercuts formed in respective portions of a dielectric layer located adjacent to opposite sidewalls of the gate feature, wherein the undercuts extend beyond respective sidewalls of the gate feature and away from the central portion of the fin structure. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method of making a semiconductor device, comprising:
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forming a fin structure on a substrate; forming a gate feature that traverses the fin structure to overlay a central portion of the fin structure; forming a dielectric layer adjacent to opposite sidewalls of the gate feature; forming undercuts in respective portions of the dielectric layer located adjacent to opposite sidewalls of the gate feature, wherein the undercuts extend away from respective sidewalls of the gate feature and away from the central portion of the fin structure, and wherein the gate feature further extends along the fin structure to overlay opposite side portions of the fin structure located in respective undercuts; forming a pair of source/drain features, along the fin structure, that are disposed at respective sides of the gate feature; and forming an oxide layer disposed between the fin structure and the gate feature. - View Dependent Claims (18, 19, 20)
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Specification