Methods and apparatus for metal silicide deposition
Methods and apparatuses for processing substrates, such as during metal silicide applications, are provided. In one or more embodiments, a method of processing a substrate includes depositing an epitaxial layer on the substrate, depositing a metal silicide seed layer on the epitaxial layer, and exposing the metal silicide seed layer to a nitridation process to produce a metal silicide nitride layer from at least a portion of the metal silicide seed layer. The method also includes depositing a metal silicide bulk layer on the metal silicide nitride layer and forming or depositing a nitride capping layer on the metal silicide bulk layer, where the nitride capping layer contains a metal nitride, a silicon nitride, a metal silicide nitride, or a combination thereof.
1. A method of processing a substrate, comprising:
depositing an epitaxial layer on the substrate;
depositing a metal silicide seed layer on the epitaxial layer;
exposing the metal silicide seed layer to a nitridation process to produce a metal silicide nitride layer from at least a portion of the metal silicide seed layer;
depositing a metal silicide bulk layer on the metal silicide nitride layer; and
forming or depositing a nitride capping layer on the metal silicide bulk layer, wherein the nitride capping layer comprises a metal nitride, a silicon nitride, a metal silicide nitride, or a combination thereof.
2. The method of claim 1 , wherein the metal silicide seed layer comprises titanium silicide or nickel silicide.
3. The method of claim 1 , wherein the metal silicide seed layer has a thickness of about 0.2 nm to about 2.5 nm.
4. The method of claim 1 , wherein the nitridation process comprises:
heating the substrate to a temperature of about 300° C. to about 600° C.;
generating a plasma from a reagent gas comprising ammonia; and
exposing the metal silicide seed layer to the plasma.
5. The method of claim 4 , wherein the substrate is heated to a temperature of about 400° C. to about 500° C., and the nitridation process lasts for about 0.5 seconds to about 5 minutes.
6. The method of claim 1 , wherein the metal silicide bulk layer comprises titanium silicide or nickel silicide.
7. The method of claim 1 , wherein the metal silicide bulk layer has a thickness of about 4 nm to about 20 nm.
8. The method of claim 1 , further comprising exposing the substrate to a clean process prior to depositing the epitaxial layer.
9. The method of claim 8 , wherein the clean process comprises:
generating a plasma from a reagent gas comprising hydrogen (H 2 ); and
exposing the substrate to the plasma.
10. The method of claim 8 , wherein the clean process comprises:
generating a plasma from a reagent gas comprising ammonia and nitrogen trifluoride; and
exposing the substrate to the plasma.
11. The method of claim 10 , wherein the substrate is exposed to the plasma for a period of about 0.1 seconds to about 10 minutes.
12. The method of claim 1 , further comprising exposing the epitaxial layer to a clean process prior to depositing the metal silicide seed layer.
13. The method of claim 12 , wherein the clean process comprises:
generating a plasma from a reagent gas comprising hydrogen (H 2 ); and
exposing the epitaxial layer to the plasma.
14. The method of claim 12 , wherein the clean process comprises:
generating a plasma from a reagent gas comprising ammonia and nitrogen trifluoride; and
exposing the epitaxial layer to the plasma.
15. The method of claim 1 , wherein the metal nitride in the nitride capping layer comprises titanium nitride or nickel nitride.
16. The method of claim 1 , wherein forming or depositing the nitride capping layer on the metal silicide bulk layer further comprises:
exposing the metal silicide bulk layer to a nitridation process to convert at least a portion of the metal silicide bulk layer to the metal silicide nitride while producing the nitride capping layer comprising the metal silicide nitride; or
depositing a metal nitride layer by a vapor deposition process while producing the nitride capping layer comprising the metal nitride; or
depositing a metal layer by a vapor deposition process and exposing the metal layer to a nitridation process to convert the metal layer to the metal nitride while producing the nitride capping layer comprising the metal nitride; or
depositing a silicon nitride layer by a vapor deposition process while producing the nitride capping layer comprising the silicon nitride.
17. The method of claim 1 , wherein the epitaxial layer is a source/drain film in an nMOS or pMOS device.
18. A method of processing a substrate, comprising:
depositing an epitaxial layer on the substrate;
exposing the epitaxial layer to a clean process; then
depositing a metal silicide seed layer on the epitaxial layer, wherein the metal silicide seed layer comprises titanium silicide or nickel silicide, and wherein the metal silicide seed layer has a thickness of about 0.2 nm to about 2.5 nm;
exposing the metal silicide seed layer to a nitridation process to produce a metal silicide nitride layer from at least a portion of the metal silicide seed layer;
depositing a metal silicide bulk layer on the metal silicide nitride layer, wherein the metal silicide bulk layer comprises titanium silicide or nickel silicide, and wherein the metal silicide bulk layer has a thickness of about 4 nm to about 20 nm; and
forming or depositing a nitride capping layer on the metal silicide bulk layer, wherein the nitride capping layer comprises a metal nitride, a silicon nitride, a metal silicide nitride, or a combination thereof.
19. The method of claim 18 , wherein the nitridation process comprises:
heating the substrate to a temperature of about 300° C. to about 600° C.;
generating a plasma from a reagent gas comprising ammonia; and
exposing the metal silicide seed layer to the plasma.