Methods for fabricating a CMOS integrated circuit having a dual stress layer (DSL)

1. A method for fabricating a CMOS integrated circuit comprising:

epitaxially growing embedded silicon germanium in regions of a semiconductor substrate;

forming SiGe-stressed source and drain regions in the embedded silicon germanium;

forming non-SiGe-stressed source and drain regions in the semiconductor substrate;

forming nickel silicide contacts in the SiGe-stressed source and drain regions and in the non-SiGe-stressed source and drain regions;

depositing a tensile insulating layer overlying the nickel silicide contacts by a first process of plasma enhanced deposition prior to depositing a compressive insulating layer;

removing a portion of the tensile insulating layer overlying the SiGe-stressed source and drain regions, leaving a remaining portion of the tensile insulating layer overlying all of the non-SiGe-stressed source and drain regions and thereafter curing the remaining portion;

depositing the compressive insulating layer overlying the SiGe-stressed source and drain regions and the remaining portion of the tensile insulating layer by a second process of plasma enhanced deposition after curing the remaining portion of the tensile insulating layer; and

removing a portion of the compressive insulating layer overlying the remaining portion of the tensile insulating layer.

2. The method of claim 1 further comprising:

forming first gate electrode structures and second gate electrode structures on the semiconductor substrate.

3. The method of claim 2 , wherein epitaxially growing the embedded silicon germanium comprises:

epitaxially growing the embedded silicon germanium around and in alignment with the first gate electrode structures.

4. The method of claim 2 further comprising:

implanting conductivity determining ions into the embedded silicon germanium to form the SiGe-stressed source and drain regions in alignment with the first gate electrode structures and implanting conductivity determining ions into the semiconductor substrate to form the non-SiGe-stressed source and drain regions in alignment with the second gate electrode structures.

5. The method of claim 1 wherein curing the remaining portion comprises exposing the remaining portion to ultraviolet radiation.

6. The method of claim 5 wherein exposing the remaining portion to ultraviolet radiation comprises exposing the remaining portion to ultraviolet radiation to raise the remaining portion to a temperature of about 400° C.

7. The method of claim 6 wherein depositing a tensile insulating layer comprises depositing a silicon nitride layer by a process of plasma enhanced deposition at a temperature of about 400° C.

8. A method for fabricating a CMOS integrated circuit comprising:

forming first gate structures and second gate structures on a semiconductor substrate;

epitaxially growing embedded SiGe in portions of the semiconductor substrate around and in alignment with the first gate structures;

forming SiGe-stressed source and drain regions in the embedded SiGe around the first gate structures and non-stressed source and drain regions around the second gate structures;

forming nickel silicide contacts in the SiGe-stressed source and drain regions and in the non-stressed source and drain regions;

depositing a tensile nitride layer overlying the nickel silicide contacts in the SiGe-stressed source and drain regions and in the non-stressed source and drain regions by a first process of plasma enhanced chemical vapor deposition prior to depositing a compressive nitride layer;

removing a portion of the tensile nitride layer overlying the SiGe-stressed source and drain regions and thereafter curing the tensile nitride layer overlying all of the nickel silicide contacts in the non-stressed source and drain regions with ultraviolet radiation; and

depositing the compressive nitride layer overlying the SiGe-stressed source and drain regions by a second process of plasma enhanced chemical vapor deposition after curing the tensile nitride layer.

9. The method of claim 8 wherein curing the tensile nitride layer comprises curing the nitride layer at a temperature of about 400° C.

10. The method of claim 9 wherein depositing a tensile nitride layer comprises depositing the tensile nitride layer at a temperature of about 400° C.

11. The method of claim 8 further comprising removing a portion of the compressive nitride layer overlying the non-stressed source and drain regions.

12. A method for fabricating a CMOS integrated circuit comprising:

depositing a tensile stress layer overlying a semiconductor substrate including SiGe-stressed source and drain regions and non-stressed source and drain regions by a first process of plasma enhanced deposition prior to depositing a compressive stress layer overlying the semiconductor substrate, wherein nickel silicide contacts are formed overlying the SiGe-stressed source and drain regions and the non-stressed source and drain regions;

removing the tensile stress layer overlying the SiGe-stressed source and drain regions and leaving a remaining portion of the tensile stress layer covering the non-stressed source and drain regions before applying a curing radiation;

applying a curing radiation to the remaining portion; and

depositing the compressive stress layer overlying the semiconductor substrate and the remaining portion by a second process of plasma enhanced deposition after applying the curing radiation.

13. The method of claim 12 wherein applying a curing radiation comprises ultraviolet irradiating the remaining portion to a temperature of about 400° C.

14. The method of claim 13 wherein depositing a tensile stress layer comprises depositing a tensile nitride layer at a temperature of about 400° C.