Uniaxially strained nanowire structure

1. A semiconductor device, comprising:

a uniaxially strained nanowire disposed above a substrate, the uniaxially strained nanowire comprising:

a discrete channel region disposed in the uniaxially strained nanowire, the discrete channel region having a current flow direction along the direction of the uniaxial strain; and

source and drain regions disposed in the nanowire, on either side of the discrete channel region, wherein the source and drain regions are discrete;

a gate electrode stack completely surrounding the discrete channel region;

a first contact completely surrounding the discrete source region; and

a second contact completely surrounding the discrete drain region.

2. The semiconductor device of claim 1 , wherein the uniaxially strained nanowire consists essentially of silicon and the uniaxial strain is a uniaxial tensile strain.

3. The semiconductor device of claim 1 , wherein the uniaxially strained nanowire consists essentially of silicon germanium (Si x Ge y , where 0<x<100, and 0<y<100) and the uniaxial strain is a uniaxial compressive strain.

4. The semiconductor device of claim 3 , wherein x is approximately 30 and y is approximately 70.

5. The semiconductor device of claim 1 , wherein the uniaxially strained nanowire is disposed above a bulk crystalline substrate having an intervening dielectric layer disposed thereon.

6. The semiconductor device of claim 1 , wherein the uniaxially strained nanowire is disposed above a bulk crystalline substrate having no intervening dielectric layer disposed thereon.

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

a pair of spacers disposed between the gate electrode stack and the first and second contacts.

8. The semiconductor device of claim 7 , wherein a portion of the uniaxially strained nanowire under one or both of the spacers is non-discrete.

9. A method of fabricating a semiconductor device, the method comprising:

forming a uniaxially strained nanowire above a substrate, the uniaxially strained nanowire comprising a discrete channel region formed in the uniaxially strained nanowire, the discrete channel region having a current flow direction along the direction of the uniaxial strain, and comprising source and drain regions formed in the nanowire, on either side of the discrete channel region, wherein the source and drain regions are discrete;

forming a gate electrode stack completely surrounding the discrete channel region;

forming a first contact completely surrounding the discrete source region; and

forming a second contact completely surrounding the discrete drain region.

10. The method of claim 9 , wherein the uniaxially strained nanowire consists essentially of silicon and the uniaxial strain is a uniaxial tensile strain.

11. The method of claim 9 , wherein the uniaxially strained nanowire consists essentially of silicon germanium (Si x Ge y , where 0<x<100, and 0<y<100) and the uniaxial strain is a uniaxial compressive strain.

12. The method of claim 11 , wherein x is approximately 30 and y is approximately 70.

13. The method of claim 9 , wherein the uniaxially strained nanowire is formed above a bulk crystalline substrate having an intervening dielectric layer formed thereon.

14. The method of claim 9 , wherein the uniaxially strained nanowire is formed above a bulk crystalline substrate having no intervening dielectric layer formed thereon.

15. The method of claim 9 , further comprising:

forming a pair of spacers between the gate electrode stack and the first and second contacts.

16. The method of claim 15 , wherein a portion of the uniaxially strained nanowire under one or both of the spacers is non-discrete.