CFET with independent gate control and low parasitic capacitance
A semiconductor structure is provided that includes a second nanosheet device of a second conductivity type stacked over a first nanosheet device of a first conductivity type that is different from the second conductivity type. Each of the first and second nanosheet devices includes at least one semiconductor channel material nanosheet. One side of the least one semiconductor channel material nanosheet of both the first and second nanosheet devices contacts a dielectric material, while another side of the least one semiconductor channel material nanosheet of both the first and second nanosheet devices contacts a functional gate-containing liner that extends laterally to connect to a gate contact of each first and second nanosheet device.
1 . A semiconductor structure comprising:
a second nanosheet device of a second conductivity type stacked vertically above a first nanosheet device of a first conductivity type, wherein the first conductivity type is different from the second conductivity type, and each of the first nanosheet device and the second nanosheet device comprises at least one suspended semiconductor channel material nanosheet having a first side and a second side that is opposite the first side;
a first dielectric material layer contacting the second side of the at least one suspended semiconductor channel material nanosheet of the first nanosheet device;
a first functional gate-containing liner of a first gate structure contacting the first side of the at least one suspended semiconductor channel material nanosheet of the first nanosheet device, wherein the first gate structure further comprises a functional gate structure that wraps around the at least one suspended semiconductor channel material nanosheet of the first nanosheet device;
a second dielectric material layer located on a surface of the first dielectric material layer and contacting the first side of the at least one suspended semiconductor channel material nanosheet of the second nanosheet device;
a second functional gate-containing liner of a second gate structure contacting the second side of the at least one suspended semiconductor channel material nanosheet of the second nanosheet device, wherein the second gate structure further comprises a functional gate structure that wraps around the at least one suspended semiconductor channel material nanosheet of the second nanosheet device;
a first inner spacer located adjacent to a first end of the functional gate structure that wraps around the at least one suspended semiconductor channel material nanosheet of each of the first nanosheet device and the second nanosheet device; and
a second inner spacer located adjacent to a second end, opposite the first end, of the functional gate structure that wraps around the at least one suspended semiconductor channel material nanosheet of each of the first nanosheet device and the second nanosheet device, wherein the functional gate structure that wraps around the at least one suspended semiconductor channel material nanosheet of each of the first nanosheet device and the second nanosheet device comprises a gate dielectric material layer and a gate electrode, wherein the gate dielectric material layer is located along a sidewall of the first inner spacer, but not the second inner spacer.
2 . The semiconductor structure of claim 1 , wherein the first functional gate-containing liner and the second functional gate-containing liner both include a vertical extending portion that extends upward from an end of a horizontal portion.
3 . The semiconductor structure of claim 2 , wherein the functional gate structure that wraps around the at least one suspended semiconductor channel material nanosheet of the first nanosheet device contacts the vertical extending portion of the first functional gate-containing liner.
4 . The semiconductor structure of claim 2 , wherein the functional gate structure that wraps around the at least one suspended semiconductor channel material nanosheet of the second nanosheet device contacts the vertical extending portion of the second functional gate-containing liner.
5 . The semiconductor structure of claim 2 , further comprising a first gate contact structure contacting the horizontal portion of the first functional gate-containing liner, and a second gate contact structure contacting the horizontal portion of the second functional gate-containing liner.
6 . The semiconductor structure of claim 1 , wherein the first nanosheet device comprises a first source/drain region of a first conductivity extending laterally outward from sidewalls of the least one suspended semiconductor channel material nanosheet of the first nanosheet device, and the second nanosheet device comprises a second source/drain region of a second conductivity, opposite the first conductivity, extending laterally outward from sidewalls of the least one suspended semiconductor channel material nanosheet of the second nanosheet device.
7 . The semiconductor structure of claim 6 , further comprising a source/drain isolation layer located between the first source/drain region and the second source/drain region.
8 . The semiconductor structure of claim 6 , further comprising a first source/drain contact structure contacting a surface of the first source/drain region, and a second source/drain contact structure contacting a surface of the second source/drain region.
9 . The semiconductor structure of claim 1 , further comprising a dielectric isolation nanosheet located between the at least one suspended semiconductor channel material nanosheet of the first nanosheet device and the at least one suspended semiconductor channel material nanosheet of the second nanosheet device.
10 . The semiconductor structure of claim 1 , wherein the first inner spacer is compositionally different from the second inner spacer.
11 . The semiconductor structure of claim 1 , wherein the first inner spacer has a width that differs from a width of the second inner spacer.
12 . The semiconductor structure of claim 1 , wherein the functional gate structure that wraps around the at least one suspended semiconductor channel material nanosheet of the first nanosheet device and the first functional gate-containing liner are of unitary construction.
13 . The semiconductor structure of claim 1 , wherein the functional gate structure that wraps around the at least one suspended semiconductor channel material nanosheet of the second nanosheet device and the second functional gate-containing liner are of unitary construction.
14 . The semiconductor structure of claim 1 , wherein the first conductivity type is p-type, and the second conductivity type is n-type.
15 . The semiconductor structure of claim 1 , wherein the first conductivity type is n-type, and the second conductivity type is p-type.
16 . The semiconductor structure of claim 1 , wherein the first nanosheet device is located on a dielectric material.