Structure and method for providing line end extensions for fin-type active regions
A semiconductor structure includes an isolation feature formed in the semiconductor substrate and a first fin-type active region. The first fin-type active region extends in a first direction. A dummy gate stack is disposed on an end region of the first fin-type active region. The dummy, gate stack may overlie an isolation structure. In an embodiment, any recess such as formed for a source/drain region in the first fin-type active region will be displaced from the isolation region by the distance the dummy gate stack overlaps the first fin-type active region.
1. A semiconductor structure, comprising:
a semiconductor substrate;
a first fin-like active region protruding from a surface of the semiconductor substrate and extending horizontally in a first direction, the first fin-like active region having a first end portion;
a second fin-like active region protruding from the surface of the semiconductor substrate and extending horizontally in the first direction and collinear with the first fin-like active region, the second fin-like active region having a second end portion;
a shallow trench isolation feature disposed at a location between the first fin-like active region and the second fin-like active region, the shallow trench isolation feature being in direct contact with the first end portion and the second end portion; and
a first functional structure, a second functional structure and a dummy structure, each comprising a main portion and two sidewall spacer elements disposed on opposite sidewalls of the respective main portions;
wherein the main portion of the first functional structure is a transistor gate electrode of a first field-effect transistor, the first field-effect transistor further comprising a first source/drain feature and a second source/drain feature formed in the first fin-like active region at opposite sides of the first functional structure, the second source/drain feature being adjacent to the first end portion; and
wherein the main portion of the second transistor gate electrode is a transistor gate electrode of a second field-effect transistor, the second field-effect transistor further comprising a third source/drain feature and a fourth source/drain feature formed in the second fin-like active region at opposite sides of the second functional structure, the third source/drain feature being adjacent to the second end portion;
wherein the main portion of the dummy structure overlies the shallow trench isolation, and the two sidewall spacer elements of the dummy structure include a first sidewall spacer element and a second sidewall spacer element, the first sidewall spacer element overlying the first end portion, and the second sidewall spacer element overlying the second end portion;
wherein the first and the second source/drain features comprise epitaxial regions, and the third and the fourth source/drain features comprise epitaxial regions;
wherein the epitaxial regions of the first and second source/drain features are spaced from the shallow trench isolation feature;
wherein the first fin-like active region is one of a first plurality of fin-like active regions, and the second fin-like active region is one of a second plurality of fin-like active regions;
wherein the first plurality of fin-like active regions are parallel to each other in a second direction perpendicular to the first direction, and the second plurality of fin-like active regions are parallel to each other in the second direction;
wherein the shallow trench isolation feature extends in the second direction between the first plurality of fin-like active regions and the second plurality of fin-like active regions;
wherein the first functional structure extends over each of the first plurality of fin-like active regions;
wherein the second functional structure extends over each of the second plurality of fin-like active regions;
wherein the first sidewall spacer extends over end portions of each of the first plurality of fin-like active regions;
and wherein the second sidewall spacer element extends over end portions each of the second plurality of fin-like active regions.
2. The semiconductor structure of claim 1 , wherein the first functional structure, the second functional structure, and the dummy structure are of substantially the same width in the first direction.
3. The semiconductor structure of claim 1 , wherein the main portion of the dummy structure is of a different material than the main portions of the first and the second functional structures.
4. The semiconductor structure of claim 3 , wherein the main portions of the first and second functional structures comprise a metal.
5. The semiconductor structure of claim 4 , wherein a gate dielectric of the first field-effect transistor comprises high-k dielectric material;
and wherein a gate dielectric of the second field-effect transistor comprises high-k dielectric material.
6. The semiconductor structure of claim 4 , wherein the main portion of the dummy structure comprises polysilicon.
7. The semiconductor structure of claim 1 , wherein the first functional structure, the second functional structure, and the dummy structure are of substantially the same width in the first direction;
wherein the main portions of the first and second functional structures comprise a metal;
wherein a gate dielectric of the first field-effect transistor comprises high-k dielectric material and a gate dielectric of the second field-effect transistor comprises high-k dielectric material;
and wherein the main portion of the dummy structure is of a different material than the main portions of the first and the second functional structures.
8. A semiconductor structure, comprising:
a semiconductor substrate having a surface;
a first transistor, comprising:
first and second source/drain regions comprising epitaxial features of a first fin-like active region at the surface of the semiconductor substrate and extending in a first direction, the second source/drain region adjacent to a first end portion of the first fin-like active region; and
a first gate stack disposed over a portion of the first fin-like active region between the first and second source/drain regions;
a second transistor, comprising:
third and fourth source/drain regions comprising epitaxial features of a second fin-like active region at the surface of the semiconductor substrate, extending in the first direction and collinear with the first fin-like active region, the third source/drain region adjacent to a second end portion of the second fin-like active region; and
a second gate stack disposed over a portion of the second fin-like active region between the third and fourth source/drain regions;
an isolation feature disposed into the surface of the semiconductor substrate between the first and second fin-like active regions, wherein the epitaxial features of the second and the third source/drain regions are spaced from the isolation feature; and
a dummy structure disposed on the isolation feature and covering the first and second end portions of the first and second fin-like active regions.
9. The semiconductor structure of claim 8 , wherein the dummy structure comprises:
a first spacer embedding the first end portion of the first fin-like active region; and
a second spacer embedding the second end portion of the second fin-like active region.
10. The semiconductor structure of claim 9 , wherein the dummy structure further comprises:
a main portion disposed between the first and second spacers and over the isolation feature.
11. The semiconductor structure of claim 8 , wherein the first fin-like active region is one of a first plurality of fin-like active regions, and the second fin-like active region is one of a second plurality of fin-like active regions;
wherein the first plurality of fin-like active regions are parallel to each other and arranged in a second direction perpendicular to the first direction, and the second plurality of fin-like active regions are parallel to each other and arranged in the second direction;
wherein the isolation feature and dummy structure extend in the second direction between the first plurality of fin-like active regions and the second plurality of fin-like active regions.
12. The semiconductor structure of claim 11 , wherein the first gate stack extends over each of the first plurality of fin-like active regions;
and wherein the second gate stack extends over of the second plurality of fin-like active regions.
13. A semiconductor structure, comprising:
a semiconductor substrate;
a first fin-like active region at a surface of the semiconductor substrate and extending in a first direction, the first fin-like active region having a first end portion;
a second fin-like active region at the surface of the semiconductor substrate, extending in the first direction and collinear with the first fin-like active region, the second fin-like active region having a second end portion;
an isolation feature disposed into the surface of the substrate at a location between the first fin-like active region and the second fin-like active region, the isolation feature being in direct contact with the first end portion and the second end portion;
a dummy structure comprising a first spacer element and a second spacer element, the first spacer element overlying the first end portion and the second spacer element overlying the second end portion;
a first transistor gate disposed over the first fin-like active region between a first source/drain feature of the first fin-like active region and a second source/drain feature of the first fin-like active region, the second source/drain feature being adjacent to the first end portion;
a second transistor gate disposed over the second fin-like active region between a third source/drain feature of the second fin-like active region and a fourth source/drain feature of the second fin-like active region, the third source/drain feature being adjacent to the second end portion;
wherein the first and the second source/drain features comprise epitaxially grown regions in the first fin-like active region, and the third and the fourth source/drain features comprise epitaxially grown regions in the second fin-like active region;
and wherein the first end portion is disposed between the isolation feature and the second source/drain feature, and the second end portion is disposed between the isolation feature and the third source/drain feature, such that the epitaxial features of the second and the third source/drain regions are spaced from the isolation feature.
14. The semiconductor structure of claim 13 , wherein the first fin-like active region is one of a first plurality of fin-like active regions, and the second fin-like active region is one of a second plurality of fin-like active regions;
wherein the first plurality of fin-like active regions are parallel to each other and arranged in a second direction perpendicular to the first direction, and the second plurality of fin-like active regions are parallel to each other and arranged in the second direction;
wherein the isolation feature extends in the second direction between the first plurality of fin-like active regions and the second plurality of fin-like active regions;
wherein the first transistor gate extends in the second direction over each of the first plurality of fin-like active regions;
and wherein the second transistor gate extends in the second direction over each of the second plurality of fin-like active regions.
15. The semiconductor structure of claim 14 , wherein the dummy structure extends in the second direction over the isolation feature.
16. The semiconductor structure of claim 15 , wherein the dummy structure further comprises:
a dummy element disposed over the isolation feature and between the first and second spacer elements.