Semiconductor structure

1. A semiconductor structure, comprising:

a base substrate including a semiconductor substrate having a PMOS region and an NMOS region and a plurality of fins on the semiconductor substrate;

a gate layer across the plurality of fins by covering portions of top and sidewall surfaces of the fins;

shallow trench isolation structures formed on the semiconductor substrate, top surfaces of the shallow trench isolation structures are lower than top surfaces of the plurality of fins;

a P-type doped epitaxial layer formed in the fins at both sides of the gate layer in the PMOS region;

an N-type doped epitaxial layer formed in the fins at both sides of the gate layer in the NMOS region;

an interlayer dielectric layer formed over the semiconductor substrate exposing the P-type doped epitaxial layer and the N-type doped epitaxial layer; and

a metal silicide layer formed on a portion of the P-type doped epitaxial layer and a portion of the N-type doped epitaxial layer not covered by the interlayer dielectric layer;

wherein:

a portion of the N-type doped epitaxial layer exposed by an N-region mask layer is processed by an N-type dopant segregated Schottky doping process to form a doped region on top of a remaining portion of the N-type doped epitaxial layer;

along a direction perpendicular to a length direction of the fin, a width of a bottom of the N-type epitaxial layer is greater than a width of the fin, and a width of a bottom of the P-type epitaxial layer is greater than the width of the fin; and

a portion of the metal silicide layer is formed between the bottom of the N-type epitaxial layer and the top surfaces of the shallow trench isolation structures, another portion of the metal silicide layer is formed between the bottom of the P-type epitaxial layer and the top surfaces of the shallow trench isolation structures.

2. The semiconductor structure according to claim 1 , wherein:

doping ions of the N-type dopant segregated Schottky doping process include at least one of P ions, As ions and Sb ions.

3. The semiconductor structure according to claim 2 , wherein:

the N-type dopant segregated Schottky (DSS) doping process is an ion implantation process;

an implanting energy of the ion implantation process is in a range of approximately 100 eV-1 keV; and

an implanting dosage of the ion implantation process is in a range of approximately 1E14 atom/cm 2 -1E16 atom/cm 2 .

4. The semiconductor structure according to claim 1 , wherein:

a height difference between top surfaces of the fins under the N-type doped epitaxial layer and top surfaces of the shallow trench isolation structures is in range approximately from −3 nm to 3 nm.

5. The semiconductor structure according to claim 1 , wherein:

the N-region mask layer is made of one of silicon nitride, silicon oxide, boron nitride, silicon carbonitride, silicon boron oxycarbonitride, and silicon oxynitride.

6. The semiconductor structure according to claim 1 , wherein:

a height difference between top surfaces of the fins under the P-type doped epitaxial layer and top surfaces of the shallow trench isolation structures is in range approximately from −3 nm to 3 nm.

7. The semiconductor structure according to claim 1 , further comprising:

a contact plug, electrically contacting with the P-type doped epitaxial layer and the N-type doped epitaxial layer.

8. The semiconductor structure according to claim 7 , further comprising:

a metal layer formed on the metal silicide layer and the semiconductor substrate; and

a barrier layer between the metal layer and the contact plug.

9. The semiconductor structure according to claim 1 , wherein:

a top portion of the N-type epitaxial layer is doped with certain doping ions.

10. The semiconductor structure according to claim 1 , wherein doping ions of the N-type dopant segregated Schottky doping process include at least one of P ions or As ions.