Fin field effect transistors having vertically stacked nano-sheet
The present disclosure describes a structure including a fin field effect transistor (finFET) and a nano-sheet transistor on a substrate and a method of forming the structure. The method can include forming first and second vertical structures over a substrate, where each of the first and the second vertical structures can include a buffer region and a first channel layer formed over the buffer region. The method can further include disposing a masking layer over the first channel layer of the first and second vertical structures, removing a portion of the first vertical structure to form a first recess, forming a second channel layer in the first recess, forming a second recess in the second channel layer, and disposing an insulating layer in the second recess.
1. A semiconductor device, comprising:
a fin field effect transistor (finFET) on a substrate, wherein the finFET comprises:
a first fin over the substrate; and
a first gate structure disposed over a top and sides of a portion of the first fin; and
a nano-sheet transistor on the substrate, wherein the nano-sheet transistor comprises:
a vertical structure over the substrate, wherein the vertical structure comprises a plurality of nano-sheet layers;
a shallow trench isolation region adjacent to the vertical structure and having a non-planar top surface; and
a second gate structure surrounding a top, sides, and a bottom of each of the plurality of nano-sheet layers of the vertical structure, wherein a gate length of the second gate structure is shorter than a gate length of the first gate structure.
2. The semiconductor device of claim 1 , wherein a ratio of the gate length of the first gate structure to the gate length of the second gate structure is greater than about 2.
3. The semiconductor device of claim 1 , wherein the first fin comprises a single semiconductor layer, wherein:
a bottom of the single semiconductor layer is in contact with the substrate; and
a top of the single semiconductor layer comprises the top of the first fin.
4. The semiconductor device of claim 1 , further comprising:
a source/drain epitaxial stack over the first fin and in contact with the first gate structure; and
an other source/drain epitaxial stack over the vertical structure and in contact with the second gate structure.
5. The semiconductor device of claim 1 , wherein the finFET further comprises a second fin disposed over the substrate, wherein a separation between the first and the second fins is smaller than an other separation between the first fin and the vertical structure.
6. The semiconductor device of claim 1 , wherein the finFET further comprises a second fin disposed over the substrate, wherein:
the first and the second fins comprise a single semiconductor material; and
the first gate structure is disposed over a top and sides of the second fin.
7. A device, comprising:
a substrate;
a field effect transistor (finFET) on the substrate, the finFET having a first channel length, wherein the finFET comprises a channel region, a buffer region under the channel region, and a shallow trench isolation region adjacent to the buffer region and having a non-planar top surface; and
a gate-all-around FET (GAAFET) on the substrate, the GAAFET having a second channel length different from the first channel length, wherein the GAAFET and the finFET are arranged as neighboring transistors.
8. The device of claim 7 , wherein a separation between the finFET and the GAAFET is about 50 nm.
9. The device of claim 7 , wherein the finFET comprises two side-by-side channel layers separated by a dielectric material.
10. The device of claim 9 , wherein the dielectric material has a width less than about 90 nm.
11. The device of claim 7 , wherein the GAAFET comprises a vertically-stacked channel region including multiple channels.
12. The device of claim 7 , wherein the finFET and GAAFET comprise high-k gate dielectrics having substantially equal thicknesses.
13. The device of claim 7 , wherein the finFET has a gate length between about 2 and about 5 times longer than a gate length of the GAAFET.
14. The device of claim 7 , wherein the finFET has a wider gate width than a gate width of the GAAFET.
15. The device of claim 7 , wherein the finFET and GAAFET have substantially equal gate heights.
16. A device, comprising:
a fin field effect transistor (finFET) on a substrate, wherein the finFET comprises:
a fin on the substrate;
first source/drain regions extending from the fin;
a first gate structure wrapped around a portion of the fin;
first and second isolation structures, wherein the fin is disposed between the first and second isolation structures, and wherein top surfaces of the first and second isolation structures are coplanar with a top surface of the portion of the fin; and
a plurality of side-by-side channels under the first gate structure and disposed between the first source/drain regions; and
a gate-all-around transistor (GAAFET) on the substrate, wherein the GAAFET comprises:
a nano-sheet stack on the substrate;
second source/drain regions extending from the nano-sheet stack;
a second gate structure wrapped around a portion of the nano-sheet stack; and
a plurality of vertically-stacked channels under the second gate structure and disposed between the second source/drain regions.
17. The device of claim 16 , wherein the finFET and the GAAFET are separated by a distance in a range of about 50 nm to about 200 mm.
18. The device of claim 16 , wherein the plurality of vertically stacked channels have channel lengths less than about 20 nm.
19. The device of claim 16 , wherein nano-sheet layers of the nano-sheet stack have thicknesses less than about 12 nim.
20. The device of claim 16 , wherein the first and second gate structures have different widths.