Semiconductor fins for finFET devices and sidewall image transfer (SIT) processes for manufacturing the same

1. A method of forming a semiconductor structure comprising:

providing a semiconductor substrate:

forming at least one precursor semiconductor fin from the semiconductor substrate;

after forming the precursor semiconductor fin, etching through at least a portion of the at least one precursor semiconductor fin to form at least one patterned precursor semiconductor fin having a gap therein, wherein the at least one patterned precursor semiconductor fin includes a first vertical surface and a second vertical surface with the gap therebetween, the gap including a third vertical surface and a fourth vertical surface, the third vertical surface and the fourth vertical surface are between the first vertical surface and the second vertical surface;

forming a semiconductor material in the gap of the at least one patterned precursor semiconductor fin, wherein the first vertical surface and the second vertical surface laterally surround the semiconductor material, and the third vertical surface and the fourth vertical surface directly contact the semiconductor material; and

transforming the at least one patterned precursor semiconductor fin into at least one semiconductor fin including the semiconductor material therein.

2. The method of claim 1 , wherein the forming the semiconductor material in the gap comprises a selective epitaxial growth process.

3. The method of claim 1 , wherein semiconductor material is composed of a SiGe layer having a germanium content in a range from 20 atomic % to 90 atomic %.

4. The method of claim 3 , wherein the first and second vertical surfaces are both composed of silicon.

5. The method of claim 3 , wherein the first and second vertical surfaces are both composed of SiGe having a germanium content of no greater than 10 atomic %.

6. The method of claim 1 , wherein the transforming the at least one patterned precursor semiconductor fin into the at least one semiconductor fin comprises performing a condensation process.

7. The method of claim 6 , wherein the condensation process comprises thermal oxidation.

8. The method of claim 1 , wherein the forming the at least one precursor semiconductor fin comprises a sidewall image transfer process.

9. The method of claim 1 , wherein the semiconductor material formed in the gap has a height that is less than a height of each precursor semiconductor fin.

10. The method of claim 9 , further comprising forming a cap directly on a topmost surface of the semiconductor material formed in the gap prior to the transforming.

11. The method of claim 10 , wherein the cap has a topmost surface that is coplanar with a topmost surface of each precursor semiconductor fin.

12. The method of claim 1 , wherein an insulator layer is located beneath the semiconductor material, and wherein the at least one semiconductor fin has a bottommost surface that is in direct physical contact with a topmost surface of the insulator layer.

13. The method of claim 1 , wherein the at least one semiconductor fin has a bottommost surface that is in direct physical contact with a topmost surface of a remaining semiconductor material portion of the semiconductor substrate.

14. The method of claim 1 , further comprising forming a gate structure on physically exposed surfaces of the at least one semiconductor fin.

15. The method of claim 1 , wherein the etching extends partially through a central portion of the at least one precursor semiconductor fin.

16. The method of claim 1 , wherein the etching extends externally through a central portion of the at least one precursor semiconductor fin.