Conductive feature formation and structure

1. A method of semiconductor processing, the method comprising:

depositing a metal layer in an opening through one or more dielectric layers to a source/drain region on a substrate, the metal layer being along the source/drain region and along a sidewall of the one or more dielectric layers that at least partially defines the opening;

nitriding the metal layer comprising performing a multiple plasma process that includes at least one directional-dependent plasma process to cause nitridation of a first portion of the metal layer along the sidewall of the one or more dielectric layers and partial nitridation of a second portion of the metal layer along the source/drain region, wherein an un-nitridated portion of the metal layer remains un-nitrided by the multiple plasma process;

forming a silicide region comprising reacting the un-nitrided portion of the metal layer with a portion of the source/drain region; and

disposing a conductive material in the opening on the nitrided first portion of the metal layer and the nitrided second portion of the metal layer.

2. The method of claim 1 , wherein depositing the metal layer comprises using a directional-dependent deposition process.

3. The method of claim 1 , wherein, as deposited, the metal layer has a first thickness along the sidewall of the one or more dielectric layers and a second thickness along the source/drain region, the second thickness being greater than the first thickness.

4. The method of claim 1 , wherein performing the multiple plasma process comprises:

performing a first plasma process comprising using a first nitrogen-containing plasma; and

after performing the first plasma process, performing a second plasma process comprising using a second nitrogen-containing plasma, wherein a directional-dependency of the second plasma process is greater than a directional-dependency of the first plasma process.

5. The method of claim 1 , wherein performing the multiple plasma process comprises:

performing a first plasma process comprising using a first nitrogen-containing plasma; and

after performing the first plasma process, performing a second plasma process comprising using a second nitrogen-containing plasma, wherein a pressure of the first plasma process is greater than a pressure of the second plasma process.

6. The method of claim 5 , wherein performing the first plasma process comprises performing multiple cycles, wherein each cycle comprises:

exposing the metal layer to the first nitrogen-containing plasma for a first duration; and

removing exposure of the metal layer from the first nitrogen-containing plasma for a second duration.

7. The method of claim 1 , wherein performing the multiple plasma process comprises:

performing a first plasma process comprising using a first nitrogen-containing plasma; and

after performing the first plasma process, performing a second plasma process comprising using a second nitrogen-containing plasma, wherein a density and an energy of the first plasma process is greater than a density and an energy of the second plasma process, respectively.

8. The method of claim 1 , wherein depositing the metal layer, nitriding the metal layer, and forming the silicide region are performed in the absence of a fluid comprising carbon and in the absence of a fluid comprising fluorine.

9. A method for semiconductor processing, the method comprising:

forming an opening through one or more dielectric layers to a semiconductor material;

depositing a metal layer in the opening, thicknesses of the metal layer varying depending on an orientation of a respective supporting surface of the metal layer;

exposing the metal layer to a first nitrogen-containing plasma;

exposing the metal layer to a second nitrogen-containing plasma, the first nitrogen-containing plasma and the second nitrogen-containing plasma each converting at least a first portion of the metal layer to a metal nitride layer, the second nitrogen-containing plasma having a greater directional-dependency than the first nitrogen-containing plasma;

reacting a second portion of the metal layer to the semiconductor material to form a silicide region on the semiconductor material, the silicide region being disposed between the semiconductor material and the metal nitride layer; and

forming a conductive material in the opening on the metal nitride layer.

10. The method of claim 9 , wherein the metal nitride layer contacts a sidewall of the one or more dielectric layers.

11. The method of claim 9 , wherein a pressure of the first nitrogen-containing plasma is greater than a pressure of the second nitrogen-containing plasma.

12. The method of claim 11 , wherein exposing the metal layer to the first nitrogen-containing plasma comprises exposing the metal layer to the first nitrogen-containing plasma in multiple cycles, wherein each cycle comprises:

exposing the metal layer to the first nitrogen-containing plasma for a first duration; and

removing exposure of the metal layer from the first nitrogen-containing plasma for a second duration.

13. The method of claim 9 , wherein a density of the first nitrogen-containing plasma is greater than a density of the second nitrogen-containing plasma.

14. The method of claim 9 , wherein an energy of the first nitrogen-containing plasma is greater than an energy of the second nitrogen-containing plasma.

15. The method of claim 9 , wherein depositing the metal layer, exposing the metal layer to the first nitrogen-containing plasma and the second nitrogen-containing plasma, and reacting the second portion of the metal layer to the semiconductor material do not include using a fluid comprising carbon and do not include using a fluid comprising fluorine.

16. A method for semiconductor processing, the method comprising:

forming a source/drain region;

forming one or more dielectric layers over the source/drain region;

forming an opening through the one or more dielectric layers, wherein the source/drain region is exposed in the opening;

depositing a metal layer along sidewalls and a bottom of the opening;

performing a first nitrogen-containing plasma process on the metal layer to form a first nitridated layer, a thickness of the first nitridated layer along sidewalls of the one or more dielectric layers being about the same as a thickness of the first nitridated layer along the bottom of the opening;

performing a second nitrogen-containing plasma process on the metal layer to form a second nitridated layer, a thickness of the second nitridated layer along the sidewalls of the one or more dielectric layers being less than a thickness of the second nitridated layer along the bottom of the opening;

forming a metal silicide region by reacting at least a portion of the metal layer with the source/drain region, wherein the silicide region is disposed between the remaining portions of the source/drain region and the second nitridated layer; and

forming a conductive material in the opening on the second nitridated layer.

17. The method of claim 16 , wherein performing the first nitrogen-containing plasma process comprises performing a plurality of cycles, wherein each cycle comprises:

performing a plasma on step by exposing the metal layer to the first nitrogen-containing plasma for a first duration; and

performing a plasma off step by removing the plasma from the metal layer.

18. The method of claim 16 , wherein an entirety of the metal layer on the source/drain region is nitridated or silicided.

19. The method of claim 16 , wherein an entirety of the metal layer along sidewalls of the one or more dielectric layers is nitridated.

20. The method of claim 16 , wherein the metal silicide region directly contacts at least one of the one or more dielectric layers.