Semiconductor device and method for manufacturing the same

1. A semiconductor device, comprising:

a non-insulator structure formed in one of a source/drain region and a gate structure;

at least one carbon nano-tube (CNT) over the non-insulator structure;

a dielectric layer surrounding the CNT; and

a graphene-based conductive layer over the at least one CNT.

2. The semiconductor device of claim 1 , further comprising:

a conductive material filling interspaces between a plurality of the at least one CNTs.

3. The semiconductor device of claim 2 , wherein the non-insulator structure comprises a metal silicide, and the metal silicide and the conductive material comprise the same metal.

4. The semiconductor device of claim 1 , further comprising:

a catalyst layer between the at least one CNT and the non-insulator structure.

5. The semiconductor device of claim 4 , wherein the catalyst layer and the non-insulator structure comprise the same metal.

6. The semiconductor device of claim 1 , further comprising:

a catalyst layer between the graphene-based conductive layer and the at least one CNT.

7. The semiconductor device of claim 6 , wherein the catalyst layer wraps around the graphene-based conductive layer.

8. The semiconductor device of claim 1 , further comprising:

a conductor, wherein the graphene-based conductive layer wraps around the conductor.

9. The semiconductor device of claim 8 , wherein a top surface of the conductor is substantially level with an end surface of the graphene-based conductive layer.

10. A semiconductor device, comprising:

a non-insulator structure;

a carbon nano-tube (CNT) electrically connected to the non-insulator structure;

a first dielectric layer, the CNT being within the first dielectric layer;

a second dielectric layer over the first dielectric layer; and

a U-shaped graphene-based conductive layer within the second dielectric layer and electrically connected to the CNT.

11. The semiconductor device of claim 10 , further comprising:

a first catalyst layer; and

a second catalyst layer, wherein the CNT is in between the first catalyst layer and the second catalyst layer.

12. The semiconductor device of claim 11 , wherein the CNT is in contact with the first catalyst layer.

13. The semiconductor device of claim 11 , wherein the U-shaped graphene-based conductive layer is in contact with the second catalyst layer.

14. The semiconductor device of claim 11 , further comprising:

a metal wrapping around the CNT.

15. The semiconductor device of claim 11 , further comprising:

a metal, wherein the U-shaped graphene-based conductive layer is disposed on sidewalls and a bottom surface of the metal.

16. A method for manufacturing a semiconductor device, comprising:

forming a hole in a first dielectric layer over a non-insulator structure;

forming a carbon nano-tube (CNT) in the hole and electrically connected to the non-insulator structure;

forming a second dielectric layer over the CNT and the first dielectric layer;

forming a trench in the second dielectric layer and exposing a top surface of the CNT; and

after forming the trench, forming a graphene-based conductive layer in the trench and electrically connected to the CNT.

17. The method of claim 16 , wherein the forming the CNT comprises:

forming a catalyst layer in the hole; and

growing the CNT over the catalyst layer.

18. The method of claim 16 , further comprising:

filling the hole with a metal after the forming the CNT.

19. The method of claim 16 , wherein the forming the graphene-based conductive layer comprises:

forming a catalyst layer in the trench; and

growing the graphene-based conductive layer over the catalyst layer.

20. The method of claim 16 , further comprising:

filling the trench with a metal after the forming the graphene-based conductive layer.