Method for forming a passivated metal layer

1. A method for forming a passivated metal layer in a gate stack of an integrated circuit, the method comprising:

providing a semiconductor substrate in a process chamber of a processing system wherein the substrate includes a high-k dielectric layer formed on an oxide, nitride, or oxynitride interface layer;

exposing the substrate to a process gas containing a rhenium-carbonyl precursor to deposit a rhenium metal layer on the high-k dielectric layer in a thermal chemical vapor deposition process; and

forming a silicon-containing passivation layer or a carbon-containing passivation layer on the rhenium metal layer, wherein the passivation layer is effective to inhibit oxygen-induced growth of Re-containing nodules on a surface of the rhenium metal layer.

2. The method according to claim 1 , further comprising annealing the silicon-containing passivation layer or the carbon-containing passivation layer to diffuse the silicon or carbon into at least a surface portion of the rhenium metal layer to convert the surface portion to a rhenium silicide or rhenium carbide passivation layer.

3. The method according to claim 1 , wherein the rhenium metal layer and the passivation layer are formed in the same processing system.

4. The method according to claim 1 , wherein the rhenium metal layer and the passivation layer are formed in different processing systems.

5. A method for forming a passivated metal layer, the method comprising:

providing a substrate in a process chamber of a processing system;

exposing the substrate to a process gas containing a rhenium-carbonyl precursor to deposit a rhenium metal layer on the substrate in a thermal chemical vapor deposition process; and

exposing the rhenium metal layer to a gas containing silicon, carbon, oxygen, or boron, or a combination of two or more thereof, and annealing the substrate to diffuse the respective silicon, carbon, oxygen or boron into at least a surface portion of the rhenium metal layer to convert the surface portion to a respective rhenium silicide, rhenium carbide, rhenium oxide or rhenium boride passivation layer effective to inhibit oxygen-induced growth of Re-containing nodules on a surface of the rhenium metal layer.

6. The method according to claim 5 , wherein the gas comprises SiH 4 , Si 2 H 6 , SiCl 2 H 2 , Si 2 Cl 6 , CH 4 , C 2 H 6 , C 2 C 4 , C 2 H 2 , C 3 H 6 , C 2 H 5 OH, CH 3 CH 2 CH 2 OH, CH 3 COCH 3 , C 4 H 8 O, O 2 , BH 4 or B 2 H 6 , or a combination of two or more thereof.

7. A method for forming a passivated metal layer, the method comprising:

providing a substrate in a process chamber of a processing system;

exposing the substrate to a process gas containing a rhenium-carbonyl precursor to deposit a rhenium metal layer on the substrate in a thermal chemical vapor deposition process; and

forming a passivation layer on the rhenium metal layer by exposing the rhenium metal layer to a metal-carbonyl precursor gas and a silicon-containing gas, a carbon-containing gas, an oxygen-containing gas, or a boron-containing gas, or a combination of two or more thereof, whereby the passivation layer is at least one of a metal silicide layer, a metal carbide layer, a metal oxide layer, or a metal boride layer, or a combination thereof, and wherein the passivation layer is effective to inhibit oxygen-induced growth of Re-containing nodules on a surface of the rhenium metal layer.

8. The method according to claim 7 , wherein the metal-carbonyl precursor comprises W(CO) 6 , Ru 3 (CO) 12 , Ni(CO) 4 , Mo(CO) 6 , Co 2 (CO) 8 , Rh 4 (CO) 12 , Re 2 (CO) 10 , Os 3 (CO) 12 , or Cr(CO) 6 , or a combination of two or more thereof, the silicon-containing gas comprises SiH 4 , Si 2 H 6 , SiCl 2 H 2 , Si 2 Cl 6 , or a combination of two or more thereof, the carbon-containing gas comprises CH 4 , C 2 H 6 , C 2 C 4 , C 2 H 2 , C 3 H 6 , C 2 H 5 OH, CH 3 CH 2 CH 2 OH, CH 3 COCH 3 , or C 4 H 8 O, or a combination of two or more thereof, the oxygen-containing gas comprises O 2 , and the boron-containing gas comprises BH 4 or B 2 H 6 , or both.

9. A method for forming a passivated Re layer, the method comprising:

providing a substrate in a process chamber of a processing system;

exposing the substrate to a process gas containing a rhenium carbonyl precursor to deposit a Re layer on the substrate in a chemical vapor deposition process;

forming a tungsten passivation layer on the Re layer; and

forming a silicon passivation layer on the tungsten passivation layer, wherein the tungsten and silicon passivation layers are effective to inhibit oxygen-induced growth of Re-containing nodules on a surface of the Re layer.

10. The method according to claim 9 , wherein the tungsten passivation layer is formed in a chemical vapor deposition process by exposing the Re layer to W(CO) 6 .

11. The method according to claim 9 , wherein the silicon passivation layer is formed in a chemical vapor deposition process by exposing the tungsten passivation layer to SiH 4 , Si 2 H 6 , SiCl 2 H 2 , or Si 2 Cl 6 , or a combination of two or more thereof.

12. The method according to claim 9 , wherein the Re layer and the tungsten and silicon passivation layers are formed in the same processing system.

13. The method according to claim 9 , wherein the Re layer and the tungsten and silicon passivation layers are formed in different processing systems.

14. The method according to claim 9 , wherein the rhenium carbonyl precursor comprises Re 2 (CO) 10 .

15. The method according to claim 9 , further comprising annealing the substrate to convert at least a portion of the tungsten and silicon passivation layers to a tungsten silicide passivation layer.

16. A method for forming a passivated metal layer, the method comprising:

providing a substrate in a process chamber of a processing system;

exposing the substrate to a process gas containing a rhenium-carbonyl precursor to deposit a rhenium metal layer on the substrate in a thermal chemical vapor deposition process; and

forming a passivation layer on the rhenium metal layer by:

first, forming a metal layer on the rhenium metal layer,

second, exposing the metal layer to a silicon-containing gas, a carbon-containing gas, a nitrogen-containing gas, an oxygen-containing gas, or a boron-containing gas, or a combination of two or more thereof, and

third, diffusing the silicon, carbon, nitrogen, oxygen and/or boron into the metal layer to convert the metal layer to a metal silicide, a metal carbide, a metal nitride, a metal oxide and/or a metal boride,

wherein the passivation layer is effective to inhibit oxygen-induced growth of Re-containing nodules on a surface of the rhenium metal layer.