Method of manufacturing a semiconductor device and a semiconductor device
A semiconductor device includes a gate structure disposed over a channel region, a source/drain epitaxial layer disposed at a source/drain region, a nitrogen containing layer disposed on the source/drain epitaxial layer, a silicide layer disposed on the nitrogen containing layer, and a conductive contact disposed on the silicide layer.
1. A method of manufacturing a semiconductor device, the method comprising:
forming a source/drain epitaxial layer at a source/drain region disposed over a substrate;
forming a nitrogen containing layer on or in a surface of the source/drain epitaxial layer by exposing the surface of the source/drain epitaxial layer to plasma formed from a nitrogen containing gas that is a mixed gas of N 2 and Ar or to an NH 3 gas while heating the substrate at a temperature between 475° C. to 550° C.;
forming a metal layer over the nitrogen containing layer; and
forming an alloy layer of an element of the source/drain epitaxial layer over the source/drain region and an element of the metal layer,
wherein after the nitrogen containing layer is formed, an annealing operation at a temperature 475° C. or higher is performed.
2. The method of claim 1 , wherein the nitrogen containing layer is formed by exposing the surface of the source/drain epitaxial layer to the NH 3 gas.
3. The method of claim 1 , wherein the metal layer is a Ni layer, a W layer or a Ta layer.
4. The method of claim 1 , wherein the metal layer is a Ti layer.
5. The method of claim 1 , wherein the nitrogen containing layer contains nitrogen in an amount of at least 20 atomic %.
6. The method of claim 5 , wherein a thickness of the nitrogen containing layer containing nitrogen in an amount of at least 20 atomic % is in a range from 5 nm to 10 nm.
7. The method of claim 1 , wherein a peak nitrogen amount in the nitrogen containing layer is in a range from 50 atomic % to 95 atomic %.
8. The method of claim 1 , wherein the metal layer is a W layer.
9. The method of claim 1 , wherein the nitrogen containing layer is formed by exposing the surface of the source/drain epitaxial layer to the NH 3 .
10. A method of manufacturing a semiconductor device, the method comprising:
forming a source/drain epitaxial layer at a source/drain region disposed over a substrate;
performing a first implantation operation to introduce first ions into the source/drain epitaxial layer;
performing a second implantation operation to introduce second ions different from the first ions into the source/drain epitaxial layer;
performing a first annealing operation;
forming a nitrogen containing layer on or in a surface of the source/drain epitaxial layer by exposing the surface of the source/drain epitaxial layer to plasma formed from a nitrogen containing gas that is mixed gas of N 2 and Ar, or to an NH 3 gas while heating the substrate at a temperature between 475° C. to 550° C.;
forming a metallic layer over the nitrogen containing layer; and
forming an alloy layer of an element of the source/drain epitaxial layer over the source/drain region and an element of the metallic layer,
wherein after the nitrogen containing layer is formed, an annealing operation at a temperature 475° C. or higher is performed.
11. The method of claim 10 , wherein the source/drain epitaxial layer includes SiGe.
12. The method of claim 11 , wherein the first ions are Ge ions.
13. The method of claim 11 , wherein the second ions include boron.
14. The method of claim 10 , wherein the first annealing operation includes laser annealing.
15. The method of claim 10 , wherein the metallic layer is a Ni layer or a W layer.
16. The method of claim 10 , wherein the nitrogen containing layer is formed by exposing the surface of the source/drain epitaxial layer to the NH 3 .
17. A method of manufacturing a semiconductor device, the method comprising:
forming a source/drain epitaxial layer at a source/drain region disposed over a substrate;
forming an interlayer dielectric (ILD) layer over the source/drain epitaxial layer;
forming a contact opening in the ILD layer to expose a part of an upper surface the source/drain epitaxial layer;
forming a nitrogen containing layer on or in the upper surface of the source/drain epitaxial layer by exposing the surface of the source/drain epitaxial layer to plasma formed from mixed gas of N 2 and Ar or to an NH 3 gas while heating the substrate at a temperature between 475° C. to 550° C.;
forming a metallic layer over the nitrogen containing layer;
forming an alloy layer of an element of the source/drain epitaxial layer over the source/drain region and an element of the metallic layer; and
forming a conducive layer over the alloy layer in the contact opening,
wherein after the nitrogen containing layer is formed, an annealing operation at a temperature 475° C. or higher is performed.
18. The method of claim 17 , wherein the nitrogen containing layer is formed by exposing the surface of the source/drain epitaxial layer to the NH 3 gas.
19. The method of claim 17 , wherein the metal layer is a Ni layer.