Methods and apparatus for metal silicide deposition

1. A method of processing a substrate, comprising:

depositing a first layer on the substrate;

depositing a metal silicide seed layer on the first 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.

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 first 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 for a period of about 0.1 seconds to about 10 minutes.

11. The method of claim 1 , further comprising exposing the first layer to a clean process prior to depositing the metal silicide seed layer.

12. The method of claim 11 , wherein the clean process comprises:

generating a plasma from a reagent gas comprising hydrogen (H 2 ); and

exposing the first layer to the plasma.

13. The method of claim 11 , wherein the clean process comprises:

generating a plasma from a reagent gas comprising ammonia and nitrogen trifluoride; and

exposing the first layer to the plasma.

14. The method of claim 1 , wherein the nitride capping layer comprises a metal nitride, a silicon nitride, a metal silicide nitride, or a combination thereof.

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 first layer is a source/drain film in an nMOS or pMOS device.

18. A method of processing a substrate, comprising:

depositing a first layer on the substrate;

exposing the first layer to a clean process; then

depositing a metal silicide seed layer on the first layer, wherein the metal silicide seed layer comprises titanium silicide or nickel silicide;

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

forming or depositing a nitride capping layer on the metal silicide bulk layer.

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.

20. The method of claim 18 , wherein the metal silicide bulk layer has a thickness of about 4 nm to about 50 nm.

21. A method of processing a substrate, comprising:

depositing a silicon-containing layer on the substrate;

exposing the silicon-containing layer to a clean process; then

depositing a metal silicide seed layer on the silicon-containing layer, wherein the metal silicide seed layer comprises titanium silicide or nickel silicide;

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

forming or depositing a nitride capping layer on the metal silicide bulk layer.

22. The method of claim 21 , wherein the metal silicide seed layer has a thickness of about 0.2 nm to about 3 nm.