Integrated circuit with finFETs and MIM fin capacitor

1. A method of fabricating a semiconductor structure, comprising:

forming a first fin, a second fin, and a third fin of semiconductor material on a buried insulator layer atop a substrate;

forming a first finFET comprising a first dielectric and a first conductor on the first fin;

forming a second finFET comprising a second dielectric and a second conductor on the third fin;

forming a fin capacitor comprising the first conductor, the second dielectric, and the second conductor on the second fin; and

forming source and drain regions in the first finFET and the second finFET by implanting ions in the first fin and the third fin.

2. The method of claim 1 , wherein the forming a fin capacitor comprises:

forming a first capacitor conductor with the first conductor;

forming a second capacitor conductor with the second conductor; and

forming a capacitor dielectric with the second dielectric.

3. The method of claim 2 , further comprising forming the capacitor dielectric between the first capacitor conductor and the second capacitor conductor.

4. The method of claim 1 , further comprising:

simultaneously forming the first conductor in the first finFET and the fin capacitor; and

simultaneously forming the second conductor in the second finFET and the fin capacitor.

5. The method of claim 1 , further comprising forming the first dielectric of a different material than the second dielectric.

6. The method of claim 1 , further comprising forming the first conductor of a different material than the second conductor, wherein:

the first conductor comprises a first metal;

the second conductor comprises a second metal; and

the fin capacitor comprises a metal-insulator-metal (MIM) fin capacitor.

7. The method of claim 1 , further comprising forming the first dielectric with a first thickness and the second dielectric with a second thickness different from the first thickness.

8. The method of claim 1 , further comprising:

forming the first dielectric with a first thickness; and

forming the second dielectric with a second thickness, wherein the first thickness is about 1.5 to about 2 times greater than the second thickness.

9. The method of claim 1 , further comprising:

forming the first dielectric with a first thickness; and

forming the second dielectric with a second thickness, wherein the second thickness is about 1.5 to about 2 times greater than the first thickness.

10. The method of claim 1 , wherein the fin capacitor comprises:

a layer of the first dielectric on the second fin and the buried insulator layer; and

a layer of the first conductor on the layer of the first dielectric.

11. The method of claim 1 , further comprising etching unmasked portions of the first conductor, wherein the etching forms a discontinuity in the first conductor between the first fin and the second fin and removes the first conductor from the third fin.

12. A method of fabricating a semiconductor structure, comprising:

forming first, second, third, and fourth fins of semiconductor material on a buried insulator layer atop a substrate;

forming a first finFET comprising a first dielectric and a first conductor on the first fin;

forming a second finFET comprising a second dielectric and a second conductor on the second fin;

forming a metal-insulator-metal (MIM) fin capacitor comprising the first conductor, the second dielectric, and the second conductor on the third and fourth fins; and

forming source and drain regions in the first finFET and the second finFET by implanting ions in the first fin and the second fin,

wherein the first finFET has a first threshold voltage and the second finFET has a second threshold voltage different from the first threshold voltage.

13. A method of fabricating a semiconductor structure, comprising:

forming a first fin, a second fin, and a third fin of semiconductor material on a buried insulator layer atop a substrate;

forming a layer of a first dielectric on the first fin, the second fin, the third fin, and an exposed upper surface of the buried insulator layer;

forming a layer of a first conductor on the layer of the first dielectric over the first fin, the second fin, and the third fin;

forming a mask on the first conductor over the first fin and the second fin, wherein the mask leaves a first unmasked area between the first fin and the second fin and a second unmasked area surrounding the third fin;

removing the first dielectric and the first conductor from over the third fin and from between the first fin and the second fin by simultaneously etching the first unmasked area and the second unmasked area;

forming a layer of a second dielectric over the first fin, the second fin, and the third fin;

forming a layer of a second conductor over the first fin, the second fin, and the third fin; and

removing the second dielectric and the second conductor from over the first fin and from between the second fin and the third fin.

14. The method of claim 13 , further comprising forming polysilicon on the first conductor over the first fin and on the second conductor over the third fin.

15. The method of claim 14 , further comprising:

patterning the polysilicon, the first conductor, and the first dielectric to form a first gate on the first fin; and

patterning the polysilicon, the second conductor, and the second dielectric to form a second gate on the third fin.

16. The method of claim 15 , further comprising:

forming gate contacts on the first gate and the second gate;

forming source/drain regions in the first and third fin using ion implantation;

forming source/drain contacts on the first fin and the third fin;

forming at least one first capacitor contact on the first conductor adjacent the second fin; and

forming at least one second capacitor contact on the second conductor adjacent the second fin.

17. The method of claim 13 , further comprising:

forming the first dielectric of a first material and a first thickness;

forming the second dielectric of a second material different than the first material and with a second thickness different than the first thickness;

forming the first conductor of a third material; and

forming the second conductor of a fourth material different than the third material.

18. The method of claim 13 , wherein the removing the second dielectric and the second conductor from over the first fin and from between the second fin and the third fin comprises:

masking the second fin and the third fin, wherein the masking creates a third unmasked area surrounding the first fin and a fourth unmasked area between the second fin and the third fin; and

simultaneously etching the third unmasked area surrounding the first fin and the fourth unmasked area between the second fin and the third fin.

19. The method of claim 18 , wherein:

the fourth unmasked area between the second fin and the third fin includes a portion of the first conductor associated with the fin capacitor; and

the etching the fourth unmasked area exposes the portion of the first conductor associated with the fin capacitor and creates a discontinuity in the second dielectric and the second conductor between the second fin and the third fin.

20. The method of claim 13 , further comprising exposing a portion of the first conductor adjacent the second fin by removing a portion of the second conductor and a portion of the second dielectric adjacent the second fin.

21. The method of claim 20 , wherein the removing the portion of the second conductor and the portion of the second dielectric adjacent the second fin and the removing the second dielectric and the second conductor from over the first fin are performed simultaneously.

22. The method of claim 13 , wherein:

the removing the first dielectric and the first conductor from over the third fin exposes a top surface and side surfaces of the semiconductor material of the third fin; and

the forming the layer of the second dielectric over the first fin, the second fin, and the third fin comprises depositing the second dielectric on: the top surface and side surfaces of the semiconductor material of the third fin, and a portion of the buried insulator layer between the first fin and the second fin.

23. A semiconductor structure, comprising:

first, second, and third fins of semiconductor material on a buried insulator layer atop a substrate;

a first finFET comprising a portion of a layer of a first dielectric and a portion of a layer of a first conductor on the first fin, wherein the first finFET comprises first source and drain regions at doped portions of the first fin;

a second finFET comprising a portion of a layer of a second dielectric and a portion of a layer of a second conductor on the third fin, wherein the second finFET comprises second source and drain regions at doped portions of the third fin; and

a fin capacitor comprising another portion of the layer of the first conductor, another portion of the layer of the second dielectric, and another portion of the layer of the second conductor on the second fin, wherein the fin capacitor comprises a metal-insulator-metal (MIM) fin capacitor.

24. The structure of claim 23 , wherein:

the first dielectric has a first thickness;

the second dielectric has a second thickness; and

one of the following: the first thickness is about 1.5 to about 2 times larger than the second thickness, or the second thickness is about 1.5 to about 2 times larger than the first thickness.

25. The structure of claim 23 , wherein:

the first finFET is formed on the first fin;

the fin capacitor is formed on the second fin;

the second finFET is formed on the third fin;

respective portions of the layer of the first conductor are a first capacitor conductor of the fin capacitor and a gate conductor of the first finFET;

respective portions of the layer of the second conductor are a second capacitor conductor of the fin capacitor and a gate conductor of the second finFET; and

respective portions of the layer of the second dielectric are a capacitor dielectric of the fin capacitor and a gate dielectric of the second finFET.

26. The structure of claim 23 , wherein the layer of the first conductor is composed of a different material than the layer of the second conductor.

27. The structure of claim 23 , wherein the first finFET has a first threshold voltage and the second finFET has a second threshold voltage different from the first threshold voltage.