Embedded stressed nitride liners for CMOS performance improvement
View Patent ↗The present invention provides a semiconducting device including a gate region positioned on a mesa portion of a substrate; and a nitride liner positioned on the gate region and recessed surfaces of the substrate adjacent to the gate region, the nitride liner providing a stress to a device channel underlying the gate region. The stress produced on the device channel is a longitudinal stress on the order of about 275 MPa to about 450 Mpa.
1. A method of forming a gate structure comprising:
forming a gate region atop a mesa portion of a substrate, wherein a hardmask is atop said gate region;
forming sidewall spacers abutting said gate region;
forming source and drain regions;
etching said substrate selective to said hardmask and said sidewall spacers to form recessed substrate surfaces offset from said mesa portion of said substrate on which said gate region is formed, wherein said mesa portion contains a mesa top surface and mesa sidewalls located above and adjoined to said recessed surfaces, and wherein said mesa top surface is vertically offset from said recessed surfaces, wherein the sidewall spacers are present abutting said mesa top surface, wherein outer surfaces of said sidewall spacers are aligned to said mesa sidewalls;
removing the sidewall spacers to provide an exposed mesa top surface;
forming silicide regions on the exposed mesa top surface, the mesa sidewalls and the recessed surfaces; and
forming a nitride liner on at least said gate region and said silicide regions on said recessed substrate surfaces, wherein said nitride liner provides a stress to said mesa portion of said substrate underlying said gate region.
2. The method of claim 1 wherein said sidewall spacers have a width ranging from about 20 nm to about 60 nm.
3. The method of claim 1 wherein said recessed substrate surface is offset from said mesa portion of said substrate on which said gate region is formed by about 40 nm to about 100 nm.
4. The method of claim 1 wherein following said etching said substrate a metal suicide is deposited and annealed to provide suicide regions.
5. The method of claim 1 wherein said forming said nitride liner comprises plasma enhanced chemical vapor deposition or rapid thermal chemical vapor deposition.
6. The method of claim 1 wherein said nitride liner is deposited under conditions that produce a compressive stress.
7. The method of claim 1 wherein said nitride liner is deposited under conditions that produce a tensile stress.
8. The method of claim 1 wherein forming said gate region comprises:
doping at least said portion of said substrate with a well implant dopant;
depositing a gate dielectric layer atop said substrate;
depositing a gate conductor layer atop said gate dielectric;
forming said hardmask atop said gate conductor;
etching said gate conductor layer and said gate dielectric selective to said hardmask to define said gate conductor region; and
forming a sidewall oxidation layer on said gate region by thermal oxidation.
9. The method of claim 8 wherein said sidewall spacers are removed prior to said forming said nitride liner.
10. A method of forming a gate structure comprising:
forming a gate region atop a portion of a substrate, wherein a hardmask is atop said gate region;
forming sidewall spacers abutting said gate region;
forming source and drain regions;
etching said substrate selective to said hardmask and said sidewall spacers to form recessed substrate surfaces vertically offset from an upper surface of said portion of said substrate on which said gate region is formed, wherein said sidewall spacers are present on a portion of the upper surface on which the gate region is formed and sidewalls of the surface on which the gate region is formed aligned to an outer surface of said sidewall spacers;
removing the sidewall spacer to provide an exposed portion of the upper surface of said substrate;
forming silicide regions on the exposed portion of the upper surface of the substrate, the sidewalls of the surface on which the gate region is formed, and the recessed substrate surfaces; and
forming a nitride liner on at least said gate region, said silicide regions, and on said recessed substrate surfaces, wherein said nitride liner provides a stress to said portion of said substrate underlying said gate region.
11. The method of claim 10 wherein said sidewall spacers have a width ranging from about 20 nm to about 60 nm.
12. The method of claim 10 wherein said recessed substrate surface is offset from said portion of said substrate on which said gate region is formed by about 40 nm to about 100 nm.
13. The method of claim 10 wherein following said etching said substrate a metal suicide is deposited and annealed to provide silicide regions.
14. The method of claim 10 wherein said forming said nitride liner comprises plasma enhanced chemical vapor deposition or rapid thermal chemical vapor deposition.
15. The method of claim 10 wherein said nitride liner is deposited under conditions that produce a compressive stress.
16. The method of claim 10 wherein said nitride liner is deposited under conditions that produce a tensile stress.
17. The method of claim 10 wherein forming said gate region comprises:
doping at least said portion of said substrate with a well implant dopant;
depositing a gate dielectric layer atop said substrate;
depositing a gate conductor layer atop said gate dielectric;
forming said hardmask atop said gate conductor;
etching said gate conductor layer and said gate dielectric selective to said hardmask to define said gate conductor region; and
forming a sidewall oxidation layer on said gate region by thermal oxidation.