Stacked gate structures
An embodiment of the invention may include a semiconductor structure and method of manufacturing. The semiconductor structure may include a top channel and a bottom channel, wherein the top channel includes a plurality of vertically oriented channels. The bottom channel includes a plurality of horizontally oriented channels. The semiconductor structure may include a gate surrounding the top channel and the bottom channel. The semiconductor structure may include spacers located on each side of the gate. A first spacer includes a dielectric material located between the plurality of vertically oriented channels. A second spacer includes a dielectric material located between the plurality of horizontally oriented channels. This may enable spacer formation between the vertical spacers.
1. A semiconductor structure comprising:
a gate structure;
a top channel, wherein the top channel comprises at least one vertically oriented channel, wherein an entire bottom surface of the at least one vertically oriented channel is in contact with an insulator layer, and wherein a top surface and vertical surfaces of the at least one vertically oriented channel is in contact with the gate structure; and
a bottom channel, wherein the bottom channel comprises a plurality of horizontally oriented channels, and wherein the gate structure surrounds the bottom channel.
2. The semiconductor structure of claim 1 , further comprising:
a gate dielectric located on each surface of the bottom channel and on the top surface and the vertical surfaces of the at least one vertically oriented channel in contact with the gate structure, wherein the gate dielectric is further located on surfaces of the insulator layer that are not in contact with the at least one vertically oriented channel.
3. The semiconductor structure of claim 2 , wherein the gate dielectric directly contacts a bottom surface and opposite sidewalls of the insulator layer.
4. The semiconductor structure of claim 1 , wherein the top channel is part of a first transistor, and wherein the bottom channel is part of a second transistor.
5. The semiconductor structure of claim 4 , wherein the first transistor and the second transistor form a complimentary field effect transistor.
6. The semiconductor structure of claim 1 , further comprising:
top source drain regions contacting opposite surfaces of the top channel; and
bottom source drain regions contacting opposite surfaces of the bottom channel.
7. The semiconductor structure of claim 1 , wherein a top surface of the insulator layer contacts a bottom surface of top source drain regions.
8. The semiconductor structure of claim 1 , wherein a width of the insulator layer measured parallel to the gate structure is substantially equal to a width of the bottom channel measured parallel to the gate structure.
9. The semiconductor structure of claim 1 , wherein a width of the top channel measured perpendicular to the gate structure is less than a width of the insulator layer measured perpendicular to the gate structure.
10. A method of forming a semiconductor structure comprising:
forming a top channel in a semiconductor layer located above a layered nanosheet stack, wherein the top channel comprises a plurality of vertically oriented channels;
depositing a sacrificial liner between the plurality of vertically oriented channels;
forming a dummy gate over the top channel;
forming gate spacers on opposite sides of the dummy gate;
removing a portion of the sacrificial liner located beneath the gate spacers to create a spacer void; and
depositing a top spacer in the spacer void.
11. The method of claim 10 , wherein a thickness of the top spacer is different from a thickness of the gate spacers.
12. The method of claim 10 , further comprising:
forming a bottom spacer, wherein the bottom spacer comprises a dielectric material located between a plurality of horizontally oriented channels of the layered nanosheet stack and a top element comprising a dielectric material in contact with a bottom surface of the top channel and a top surface of a bottom channel.
13. The method of claim 12 , wherein a structural interface exists between the top spacer and the gate spacers.
14. The method of claim 12 , wherein the top element has a top portion and a bottom portion, wherein the top portion comprises a plurality of fin protrusions, wherein each fin protrusion is located beneath each of the plurality of vertically oriented channels, and wherein the bottom portion comprises a horizontal layer connecting each of the plurality of fin protrusions of the top portion.
15. The method of claim 10 , wherein the top channel is part of a first transistor, and wherein a bottom channel is part of a second transistor.
16. The method of claim 15 , wherein the first transistor and the second transistor form a complimentary field effect transistor.