Methods of channel stress engineering and structures formed thereby

1. A method comprising:

amorphizing a source/drain region of an NMOS portion of a substrate comprising an NMOS gate, wherein a PMOS portion of the substrate is not amorphized;

forming a stress material on a top surface and on a sidewall region of the NMOS gate and the PMOS gate; and

annealing the stress material, wherein a first dislocation is formed in a first source/drain region and a wherein a second dislocation is formed in a second source/drain region wherein a the first dislocation and the second dislocation are formed adjacent a channel region of the NMOS portion of the substrate; wherein the first and second dislocations comprise a length of between about 20 nm and about 50 nm, and wherein an angle is disposed between a top surface of the first source/drain region of the NMOS substrate and the first dislocation and wherein an angle is disposed between a top surface of the second source/drain region of the NMOS substrate and the second dislocation.

2. The method of claim 1 further comprising wherein the amorphizing is performed by an ion implant process.

3. The method of claim 1 further comprising wherein the first and second dislocations are formed in the silicon crystal lattice of the first source/drain region and the second source/drain region adjacent the channel region of the NMOS gate.

4. The method of claim 1 further comprising wherein at least one of the NMOS gate and the PMOS gate comprises a metal gate.

5. The method of claim 1 further comprising wherein the stress material comprises a dual layer film.

6. The method of claim 1 further comprising wherein the stress material disposed on the top surface and on the sidewall region of the NMOS gate and the PMOS gate is annealed at a temperature of about 600 degrees Celsius and below.

7. The method of claim 3 further comprising wherein the stress material comprises a thickness of less than about 500 angstroms.

8. The method of claim 3 further comprising wherein the first and second dislocations induces a stress in the channel region.

9. The method of claim 8 further comprising wherein the anneal causes Si re-growth rate in the wafer plane and in a plane perpendicular to current flow, leading to the formation of the first and second dislocations.

10. A method comprising:

exposing an NMOS portion of a substrate and masking a PMOS portion of the substrate with a masking material;

amorphizing a source/drain region of the NMOS portion of the substrate by ion implantation;

removing the masking material from the PMOS portion of the transistor substrate;

forming a tensile material on an NMOS gate of the NMOS portion of the substrate and on a PMOS gate of the PMOS portion of the substrate; and

annealing the tensile material, wherein a first dislocation is formed adjacent a channel region of the NMOS portion of the substrate that introduces a strain into an NMOS channel region adjacent the dislocation;

wherein the first dislocation is formed in a first source/drain region and a wherein a second dislocation is formed in a second source/drain region;

wherein the first and second dislocations comprises a length of between about 20 nm and about 50 nm, and wherein an angle is disposed between a top surface of the first source/drain region of the NMOS substrate and the first dislocation and wherein an angle is disposed between a top surface of the second source/drain region of the NMOS substrate and the second dislocation.

11. The method of claim 10 further comprising wherein the tensile material is removed from the NMOS and PMOS gates.

12. The method of claim 10 further comprising wherein the tensile material comprises a dual layer comprising a silicon nitride layer disposed on a silicon oxide layer.

13. The method of claim 10 further comprising wherein the first and second dislocations comprises edge dislocations, and wherein the edge dislocations is are not formed on the PMOS source/drain regions.