Stacked FET SRAM
A semiconductor device is provided that includes at least one stacked FET device including two top transistors stacked over a single bottom transistor. The at least one stacked FET includes a full gate cut structure that is used to separate different device areas from each other, a top gate cut structure that used to separate the two top transistors, and a bottom gate cut structure that is used to provide the single bottom transistor. The at least one FET device can be used to provide a SRAM containing six transistors.
1. A semiconductor device comprising:
a first stacked field effect transistor device present in a first device area, the first stacked field effect transistor device comprising two top transistors stacked above a single bottom transistor;
a full gate cut structure located at the periphery of the first device area, and separating the first device area from an adjacent second device area;
a top gate cut structure separating the two top transistors from each other; and
a bottom gate cut structure located laterally adjacent to the single bottom transistor and beneath one of the top transistors.
2. The semiconductor device of claim 1 , wherein each of the two top transistors wraps around at least one semiconductor channel material nanosheet of a top nanosheet-containing material stack, and the single bottom transistor wraps around at least one semiconductor channel material nanosheet of a bottom nanosheet-containing material stack.
3. The semiconductor device of claim 2 , wherein a dielectric material nanosheet is present between the bottom nanosheet-containing material stack and the top nanosheet containing material stack.
4. The semiconductor device of claim 1 , wherein a first top transistor of the two top transistors and the single bottom transistor share a shared gate structure, and a second top transistor of the two top transistors has a gate structure that is independent from the shared gate structure.
5. The semiconductor device of claim 4 , further comprising a backside gate contact structure contacting a bottommost surface of the shared gate structure and a frontside gate contact structure a topmost surface of the shared gate structure.
6. The semiconductor device of claim 5 , further comprising a backside gate cross couple contact structure contacting the backside gate contact structure, and a top gate cross couple structure contacting the frontside gate contact structure.
7. The semiconductor device of claim 4 , further comprising a frontside shared source/drain (S/D) contact structure contacting a top S/D region of the first top transistor of the two top transistors and a bottom S/D structure of the single bottom transistor, and a backside shared gate contact structure contacting a bottom S/D structure and a top S/D region of the second top transistor.
8. The semiconductor device of claim 7 , further comprising a backside shared S/D cross couple structure contacting the backside shared S/D contact structure, and a frontside shared S/D cross couple structure contacting the frontside shared S/D contact structure.
9. The semiconductor device of claim 1 , wherein the two top transistors and the single bottom transistors are components of a SRAM cell.
10. The semiconductor device of claim 1 , further comprising a frontside Vss power supply located above the two top transistors, and a backside Vdd power supply located beneath the single bottom transistor.
11. The semiconductor device of claim 1 , further comprising a second stacked field effect transistor device present in the first device area and laterally adjacent to the first stacked field effect transistor device, the second stacked field effect transistor device comprising two top transistors stacked above a single bottom transistor, wherein another top gate cut structure separates the two top transistors of the second staked field effect transistor from each other and another bottom gate cut structure is located laterally adjacent to the single bottom transistor of the second stacked field effect device and beneath one of the top transistors of the second stacked field effect device.
12. The semiconductor device of claim 11 , wherein the first stacked field effect device and the second field effect transistor device provide a 6T SRAM.
13. The semiconductor device of claim 1 , further comprising a middle-of-the-line (MOL) dielectric material layer located above the two top transistors, a back-end-of-the-line (BEOL) structure located on the MOL dielectric material layer, and a carrier wafer located on the BEOL structure.
14. The semiconductor device of claim 1 , further comprising a dielectric material layer located beneath the first stacked field effect transistor device.
15. The semiconductor device of claim 14 , wherein the backside gate cut structure has a bottommost surface that is coplanar with a bottommost surface of the dielectric material layer.
16. The semiconductor device of claim 14 , further comprising a backside power rail located beneath the dielectric material layer, the backside power rail is embedded in an interconnect dielectric material layer.
17. The semiconductor device of claim 16 , further comprising a backside power delivery network located beneath the interconnect dielectric material layer.
18. The semiconductor device of claim 1 , wherein the single bottom transistor is of a first conductivity type, and the two top transistors are of a second conductivity that is different from the first conductivity type.
19. The semiconductor device of claim 18 , the first conductivity type is p-type and the second conductivity type is n-type.
20. The semiconductor device of claim 18 , wherein the first conductivity type is n-type and the second conductivity type is p-type.