Integrated circuit structure incorporating stacked field effect transistors and method
Disclosed are integrated circuit (IC) structure embodiments that incorporate stacked pair(s) of field effect transistors (FETs) (e.g., gate-all-around FETs), including a lower FET and an upper FET on the lower FET, and various metal components that enable power and/or signal connections to the source/drain regions of those FETs. The metal components can include first buried wire(s) within an isolation region in a level below the stacked pair and a first embedded contact that electrically connects a source/drain region of the lower FET to a first buried wire. Optionally, the metal components can also include second buried wire(s) in dielectric material at the same level as the upper FET and a second embedded contact that electrically connects a source/drain region of the upper FET to a second buried wire. Also disclosed are embodiments of a method of forming such IC structure embodiments.
1. An integrated circuit structure comprising:
an isolation region on a semiconductor substrate laterally surrounding a semiconductor fin;
a first buried wire within the isolation region parallel to the semiconductor fin;
a first transistor comprising two first source/drain regions on the semiconductor fin, wherein side portions of the two first source/drain regions extend over the isolation region and wherein at least one first channel region is positioned laterally between the two first source/drain regions;
a first embedded contact electrically connecting a first source/drain region of the two first source/drain regions to the first buried wire;
a dielectric layer above the first source/drain regions and extending laterally over the first embedded contact; and
a second transistor comprising: two second source/drain regions on the dielectric layer above the two first source/drain regions, respectively; and at least one second channel region positioned laterally between the two second source/drain regions.
2. The integrated circuit structure of claim 1 , the two second source/drain regions and the at least one second channel region being aligned above the two first source/drain regions and the at least one first channel region, respectively, and the two second source/drain regions being electrically isolated from the two first source/drain regions and the first embedded contact by the dielectric layer.
3. The integrated circuit structure of claim 1 , the first transistor and the second transistor having a shared gate adjacent to the at least one first channel region and the at least one second channel region.
4. The integrated circuit structure of claim 1 , the first buried wire being one of a first buried power wire and a first buried signal wire.
5. The integrated circuit structure of claim 1 , the first embedded contact contacting a side surface of the first source/drain region and at least a top surface of the first buried wire.
6. The integrated circuit structure of claim 1 , further comprising:
an additional first buried wire in the isolation region parallel to the semiconductor fin such that the semiconductor fin is positioned laterally between two first buried wires; and
an additional first embedded contact in a different first source/drain region of the two first source/drain regions and electrically connecting the different first source/drain region to the additional first buried wire.
7. The integrated circuit structure of claim 6 , the two first buried wires comprising a first buried signal wire and a first buried power wire.
8. The integrated circuit structure of claim 1 , further comprising:
a second buried wire in dielectric material positioned laterally adjacent to a second source/drain region of the two second source/drain regions of the second transistor, wherein the second buried wire is aligned above the first buried wire; and
a second embedded contact in the second source/drain region and extending laterally to the second buried wire.
9. The integrated circuit structure of claim 8 , the second buried wire comprising one of a second buried signal wire and a second buried power wire.
10. An integrated circuit structure comprising:
an isolation region on the semiconductor substrate laterally surrounding a semiconductor fin;
two first buried wires within the isolation region, the semiconductor fin being between and parallel to the two first buried wires;
a first transistor comprising two first source/drain regions on the semiconductor fin, wherein side portions of the two first source/drain regions extend over the isolation region and wherein at least one first channel region is positioned laterally between the first source/drain regions;
two first embedded contacts in the two first source/drain regions, respectively,
wherein one of the two first embedded contacts extends vertically from one of the two first source/drain regions to one of the two first buried wires and a different one of the two first embedded contacts extends vertically from a different one of the two first source/drain regions to a different one of the two first buried wires;
a dielectric layer above the two first source/drain regions and extending laterally over the two first embedded contacts; and
a second transistor comprising: two second source/drain regions on the dielectric layer above the two first source/drain regions; and at least one second channel region positioned laterally between the second source/drain regions,
wherein the two second source/drain regions and the at least one second channel region are aligned above the first source/drain regions and the at least one first channel region, respectively, and
wherein the two second source/drain regions are electrically isolated from the two first source/drain regions and the two first embedded contacts by the dielectric layer.
11. The integrated circuit structure of claim 10 , the first transistor and the second transistor having a shared gate adjacent to the at least one first channel region and the at least one second channel region.
12. The integrated circuit structure of claim 10 , the two first buried wires comprising a first buried power wire and a first buried signal wire.
13. The integrated circuit structure of claim 10 , each first embedded contact contacting a side surface of a first source/drain region and at least a top surface and sidewall of a first buried wire.
14. The integrated circuit structure of claim 10 , further comprising:
a second buried wire within dielectric material adjacent to a second source/drain region of the two second source/drain regions, wherein the second buried is aligned above one of the two first buried wires; and
a second embedded contact in the second source/drain region and extending laterally to the second buried wire.
15. The integrated circuit structure of claim 14 , the second buried wire comprising one of a second buried signal wire and a second buried power wire.