Stacked complementary FETs featuring vertically stacked horizontal nanowires
After forming a stacked nanowire CMOS device including a first stacked nanowire array laterally surrounded by first epitaxial semiconductor regions, a second stacked nanowire array overlying the first stacked nanowire array and laterally surrounded by second epitaxial semiconductor regions, and a functional gate structure straddling over each semiconductor nanowire in the first and second stacked nanowire arrays, a common source/drain contact structure is formed on one side of the functional gate structure contacting one of the first epitaxial semiconductor regions and one of the second epitaxial semiconductor regions. A first local source/drain contact structure is formed on the opposite side of the functional gate structure contacting another of the first epitaxial semiconductor regions. After forming a trench isolation structure over the first local source/drain contact structure, a second local source/drain structure is formed overlying the first source/drain local contact structure and contacting another of the second epitaxial semiconductor regions.
1. A semiconductor structure comprising:
a plurality of vertically stacked and vertically spaced apart semiconductor nanowires located over a substrate, wherein the plurality of vertically stacked and vertically spaced apart semiconductor nanowires are organized into a lower nanowire array and an upper nanowire array overlying the lower nanowire array;
a functional gate structure straddling over the plurality of vertically stacked and vertically spaced apart semiconductor nanowires;
first epitaxial semiconductor regions of a first conductivity type laterally contacting end walls of the semiconductor nanowires in the lower nanowire array;
second epitaxial semiconductor regions of a second conductivity type opposite the first conductivity type laterally contacting end walls of the semiconductor nanowires in the upper nanowire array; and
an insulator layer located between the first epitaxial semiconductor region and the second epitaxial semiconductor regions.
2. The semiconductor structure of claim 1 , wherein a topmost surface of the insulator layer contacts bottommost surfaces of the second epitaxial semiconductor regions, and a bottommost surface of the insulator layer contacts topmost surfaces of the first epitaxial semiconductor regions.
3. The semiconductor structure of claim 1 , further comprising a common source/drain contact structure contacting one of the first epitaxial semiconductor regions and one of the second epitaxial semiconductor regions located on a first side of the functional gate structure.
4. The semiconductor structure of claim 3 , further comprising a first local source/drain contact structure contacting another of the first epitaxial semiconductor regions located on a second side of the functional gate structure opposite the first side, and a second local source/drain contact structure overlying the first local source/drain contact structure and contacting another of the second epitaxial semiconductor regions located on the second side of the functional gate structure, wherein a trench isolation structure is located between the first local source/drain contact structure and the second local source/drain contact structure.
5. The semiconductor structure of claim 4 , wherein a topmost surface of the first local source/drain contact structure is located below a topmost surface of the insulator layer.
6. The semiconductor structure of claim 4 , wherein a topmost surface of the trench isolation structure is located below topmost surfaces of the second epitaxial semiconductor regions.
7. The semiconductor structure of claim 4 , further comprising an interlevel dielectric (ILD) layer located over the second epitaxial semiconductor regions, the ILD layer laterally surrounding the functional gate structures, the common source/drain contact structure and the second local source/drain contact structure.
8. The semiconductor structure of claim 1 , wherein the functional gate structure comprises a functional gate stack having a first portion located above a topmost semiconductor nanowire of the plurality of vertically stacked and vertically spaced apart semiconductor nanowires, and a second portion located beneath each semiconductor nanowires of the plurality of vertically stacked and vertically spaced apart semiconductor nanowires.
9. The semiconductor structure of claim 8 , wherein the first portion of the functional gate stack comprises a U-shaped gate dielectric having a bottommost portion in direct contact with a topmost surface of the topmost semiconductor nanowire in the plurality of vertically stacked and vertically spaced apart semiconductor nanowires and a gate electrode located on the U-shaped gate dielectric.
10. The semiconductor structure of claim 8 , wherein the second portion of the functional gate stack comprises a gate dielectric and a gate electrode surrounded by the gate dielectric.
11. The semiconductor structure of claim 8 , wherein the insulator layer laterally contacts a portion of the second portion of the functional gate stack located between the lower nanowire array and the upper nanowire array.
12. The semiconductor structure of claim 8 , wherein the functional gate structure comprises a gate spacer present on sidewalls of the first portion of the functional gate stack.
13. The semiconductor structure of claim 12 , wherein the end walls of the semiconductor nanowires in the lower nanowire array and the end walls of the semiconductor nanowires in the upper nanowire array are vertically coincident with outer sidewalls of the gate spacer.
14. The semiconductor structure of claim 7 , wherein each of the second epitaxial semiconductor regions has faceted surfaces, wherein a void is located between each of the second epitaxial semiconductor regions and the insulator layer.
15. The semiconductor structure of claim 14 , wherein the ILD layer fills each void such that the ILD layer is in direct contact with a topmost surface of the insulator layer.
16. The semiconductor structure of claim 1 , wherein the plurality of vertically stacked and vertically spaced apart semiconductor nanowires is vertically separated from each other by a first spacing, and the lower nanowire array is separated from the upper nanowire array by a second spacing greater than the first spacing.
17. The semiconductor structure of claim 1 , wherein the first epitaxial semiconductor regions comprise phosphorous doped Si:C, and the second epitaxial semiconductor regions comprise boron doped SiGe.
18. The semiconductor structure of claim 4 , wherein each of the common source/drain contact structure, the first local source/drain contact structure and the second local source/drain contact structure comprises a contact liner and a contact conductor.
19. A semiconductor structure comprising:
a plurality of vertically stacked and vertically spaced apart semiconductor nanowires located over a substrate, wherein the plurality of vertically stacked and vertically spaced apart semiconductor nanowires are organized into a lower nanowire array and an upper nanowire array;
a functional gate structure straddling over the plurality of vertically stacked and vertically spaced apart semiconductor nanowires;
first epitaxial semiconductor regions of a first conductivity type laterally contacting end walls of the semiconductor nanowires in the lower nanowire array;
second epitaxial semiconductor regions of a second conductivity type opposite the first conductivity type laterally contacting end walls of the semiconductor nanowires in the upper nanowire array;
an insulator layer located between the first epitaxial semiconductor region and the second epitaxial semiconductor regions;
a common source/drain contact structure contacting one of the first epitaxial semiconductor regions and one of the second epitaxial semiconductor regions located on a first side of the functional gate structure; and
a first local source/drain contact structure contacting another of the first epitaxial semiconductor regions located on a second side of the functional gate structure opposite the first side, and a second local source/drain contact structure overlying the first local source/drain contact structure and contacting another of the second epitaxial semiconductor regions located on the second side of the functional gate structure, wherein a trench isolation structure is located between the first local source/drain contact structure and the second local source/drain contact structure.
20. A semiconductor structure comprising:
a plurality of vertically stacked and vertically spaced apart semiconductor nanowires located over a substrate, wherein the plurality of vertically stacked and vertically spaced apart semiconductor nanowires are organized into a lower nanowire array and an upper nanowire array;
a functional gate structure straddling over the plurality of vertically stacked and vertically spaced apart semiconductor nanowires, wherein the functional gate structure comprises a functional gate stack having a first portion located above a topmost semiconductor nanowire of the plurality of vertically stacked and vertically spaced apart semiconductor nanowires, and a second portion located beneath each semiconductor nanowires of the plurality of vertically stacked and vertically spaced apart semiconductor nanowires;
first epitaxial semiconductor regions of a first conductivity type laterally contacting end walls of the semiconductor nanowires in the lower nanowire array;
second epitaxial semiconductor regions of a second conductivity type opposite the first conductivity type laterally contacting end walls of the semiconductor nanowires in the upper nanowire array; and
an insulator layer located between the first epitaxial semiconductor region and the second epitaxial semiconductor regions.