FinFET with embedded MOS varactor and method of making same

1. A semiconductor device comprising:

a first FinFET over a substrate, wherein the first FinFET comprises a first fin;

a first body contact for the first FinFET over the substrate, wherein the first body contact comprises a second fin, and wherein the second fin is parallel to the first fin; and

a first active gate and a second active gate over the second fin, wherein a first body contact region is interposed between the first active gate and the second active gate.

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

a second FinFET over the substrate, wherein the second FinFET comprises a third fin, wherein the third fin is parallel to the first fin, and wherein the second fin is interposed between the first fin and the third fin; and

a second body contact for the second FinFET over the substrate, wherein the second body contact comprises a fourth fin, wherein the fourth fin is parallel to the first fin, and wherein the third fin is interposed between the second fin and the fourth fin.

3. The semiconductor device of claim 1 , further comprising a first dummy gate over the second fin, wherein a second body contact region is interposed between the first dummy gate and the first active gate.

4. The semiconductor device of claim 1 , wherein the first fin has a same width and a same length as the second fin.

5. The semiconductor device of claim 1 , further comprising a third active gate and a first dummy gate over the first fin, wherein a source region is interposed between the third active gate and the first dummy gate.

6. The semiconductor device of claim 1 , further comprising a third active gate and a first dummy gate over the first fin, wherein a drain region is interposed between the third active gate and the first dummy gate.

7. The semiconductor device of claim 1 , further comprising a third active gate and a fourth active gate over the first fin, wherein a source region is interposed between the third active gate and the fourth active gate.

8. The semiconductor device of claim 1 , further comprising a third active gate and a fourth active gate over the first fin, wherein a drain region is interposed between the third active gate and the fourth active gate.

9. A semiconductor device comprising:

a first FinFET over a substrate, the first FinFET comprising:

a first fin; and

a first dummy gate and a second dummy gate over the first fin; and

a first body contact for the first FinFET over the substrate, the first body contact comprising:

a second fin; and

a third dummy gate and a fourth dummy gate over the second fin, wherein a body contact region is interposed between the third dummy gate and the fourth dummy gate.

10. The semiconductor device of claim 9 , further comprising:

a second FinFET over the substrate, the second FinFET comprising:

a third fin; and

a first active gate and a second active gate over the third fin; and

a second body contact for the second FinFET over the substrate, the second body contact comprising:

a fourth fin; and

a third active gate and a fourth active gate over the fourth fin, wherein the first fin, the second fin, the third fin, and the fourth fin are parallel to each other.

11. The semiconductor device of claim 10 , wherein the third active gate and the fourth active gate are electrically coupled to a bias node thereby forming a decoupling capacitor.

12. The semiconductor device of claim 10 , wherein the third active gate and the fourth active gate are electrically coupled to a power node thereby forming a decoupling capacitor.

13. The semiconductor device of claim 9 , wherein the first FinFET further comprises a first active gate and a second active gate over the first fin, and wherein the first active gate and the second active gate are interposed between the first dummy gate and the second dummy gate.

14. The semiconductor device of claim 9 , wherein the first body contact further comprises a first active gate and a second active gate over the second fin, and wherein the first active gate and the second active gate are interposed between the third dummy gate and the fourth dummy gate.

15. The semiconductor device of claim 9 , wherein the first FinFET further comprises a source region and a drain region, and wherein the source region and the drain region are interposed between the first dummy gate and the second dummy gate.

16. A method for forming a semiconductor device, the method comprising:

forming a first FinFET comprising:

forming a first fin on a substrate;

forming a first dummy gate and a second dummy gate over the first fin, wherein the first dummy gate and the second dummy gate are separated along a longitudinal axis of the first fin; and

forming a first source region and a first drain region in the first fin; and

forming a first body contact for the first FinFET comprising:

forming a second fin on the substrate;

forming a third dummy gate and a fourth dummy gate over the second fin; and

forming a first body contact region in the second fin, the first body contact region being interposed between the third dummy gate and the fourth dummy gate.

17. The method of claim 16 , further comprising:

forming a second FinFET comprising:

forming a third fin on the substrate;

forming a first active gate and a second active gate over the third fin; and

forming a second source region and a second drain region in the third fin; and

forming a second body contact for the second FinFET comprising:

forming a fourth fin on the substrate;

forming a third active gate and a fourth active gate over the fourth fin; and

forming a second body contact region in the fourth fin, the second body contact region being interposed between the third active gate and the fourth active gate.

18. The method of claim 16 , wherein forming the first FinFET further comprises forming an active gate over the first fin, the active gate being interposed between the first source region and the first drain region.

19. The method of claim 16 , wherein forming the first body contact further comprises forming an active gate over the second fin, the active gate being interposed between the third dummy gate and the fourth dummy gate.

20. The method of claim 16 , wherein forming the first body contact further comprises:

forming a fifth dummy gate over the second fin; and

forming a second body contact region in the second fin, the fifth dummy gate being interposed between the first body contact region and the second body contact region.