High-performance FETs with embedded stressors
View Patent ↗A high-performance semiconductor structure and a method of fabricating such a structure are provided. The semiconductor structure includes at least one gate stack, e.g., FET, located on an upper surface of a semiconductor substrate. The structure further includes a first epitaxy semiconductor material that induces a strain upon a channel of the at least one gate stack. The first epitaxy semiconductor material is located at a footprint of the at least one gate stack substantially within a pair of recessed regions in the substrate which are present on opposite sides of the at least one gate stack. A diffused extension region is located within an upper surface of said first epitaxy semiconductor material in each of the recessed regions. The structure further includes a second epitaxy semiconductor material located on an upper surface of the diffused extension region. The second epitaxy semiconductor material has a higher dopant concentration than the first epitaxy semiconductor material.
1. A semiconductor structure comprising:
at least one gate stack located on an upper surface of a semiconductor substrate;
a first epitaxy semiconductor material located at a footprint of the at least one gate stack substantially within a pair of recessed regions which are present on opposite sides of said at least one gate stack, said first epitaxy semiconductor material induces a strain upon a channel of said at least one gate stack;
a diffused extension region located within an upper surface of said first epitaxy semiconductor material in each of said recessed regions; and
a second epitaxy semiconductor material located on an upper surface of said diffused extension region, wherein said second epitaxy semiconductor material has a higher dopant concentration than the first epitaxy semiconductor material.
2. The semiconductor structure of claim 1 wherein said pair of recessed regions is separated from each other by a pedestal of said semiconductor substrate.
3. The semiconductor structure of claim 2 wherein said pedestal has substantially straight sidewalls.
4. The semiconductor structure of claim 2 wherein said pedestal has an hour glass shape.
5. The semiconductor structure of claim 1 wherein said first epitaxy semiconductor material is undoped or has a dopant concentration of less than 5×10 18 atoms/cm 3 .
6. The semiconductor structure of claim 1 wherein said second epitaxy semiconductor material has a dopant concentration of greater than 1×10 19 atoms/cm 3 .
7. The semiconductor structure of claim 1 wherein said first epitaxy semiconductor material comprises SiGe.
8. The semiconductor structure of claim 1 wherein said first epitaxy semiconductor material comprises Si:C.
9. The semiconductor structure of claim 1 further comprising a halo implant region located within said semiconductor substrate, said halo region is in contact with said diffused extension region and said first epitaxy semiconductor material.
10. The semiconductor structure of claim 1 further comprising a metal semiconductor alloy located at least on an upper surface of said second epitaxy semiconductor material.
11. The semiconductor structure of claim 1 further comprising a first spacer having a base located on a surface of said semiconductor substrate and having a lateral edge in contact with a sidewall of said at least one gate stack, and a second spacer having a base located on an upper surface of said second epitaxy semiconductor material and a lateral edge in contact with a sidewall of said first spacer.
12. The semiconductor structure of claim 1 wherein no deep ion implanted source region or deep ion implanted drain region are present.
13. The semiconductor structure of claim 1 wherein said first epitaxy semiconductor material has an upper surface that is coplanar with, or extends above, said upper surface of said semiconductor substrate.
14. The semiconductor structure of claim 1 wherein said first epitaxy semiconductor material has an upper surface that is located beneath said upper surface of said semiconductor substrate.