Barrier-free approach for forming contact plugs
A method includes etching a dielectric layer of a substrate to form an opening in the dielectric layer, forming a metal layer extending into the opening, performing an anneal process, so that a bottom portion of the metal layer reacts with a semiconductor region underlying the metal layer to form a source/drain region, performing a plasma treatment process on the substrate using a process gas including hydrogen gas and a nitrogen-containing gas to form a silicon-and-nitrogen-containing layer, and depositing a metallic material on the silicon-and-nitrogen-containing layer.
1. A method comprising:
etching a dielectric layer of a substrate to form an opening in the dielectric layer;
forming a metal layer extending into the opening;
performing an anneal process, so that a bottom portion of the metal layer reacts with a semiconductor region underlying the metal layer to form a source/drain silicide region;
performing a plasma treatment process on the substrate using a process gas comprising hydrogen gas and a nitrogen-containing gas to form a silicon-and-nitrogen-containing layer; and
depositing a metallic material on the silicon-and-nitrogen-containing layer.
2. The method of claim 1 further comprising:
before the plasma treatment process, performing a thermal soaking process on the substrate using a silicon-containing process gas.
3. The method of claim 1 , wherein at a time the plasma treatment process is finished, the silicon-and-nitrogen-containing layer is free from metal therein.
4. The method of claim 1 , wherein the dielectric layer comprises silicon, and wherein when the plasma treatment process is performed, a sidewall of the dielectric layer is exposed to the opening and exposed to the hydrogen gas and the nitrogen-containing gas.
5. The method of claim 1 , wherein the plasma treatment process and at least a part of the depositing the metallic material are in-situ performed without vacuum break therebetween.
6. The method of claim 5 , wherein the depositing the metallic material comprises depositing a metal seed layer, and the depositing the metal seed layer and the plasma treatment process are in-situ performed without vacuum break in between.
7. The method of claim 1 , wherein the plasma treatment process is performed after the source/drain silicide region is formed, and wherein the silicon-and-nitrogen-containing layer extends on both of the source/drain silicide region and the dielectric layer.
8. The method of claim 1 , wherein the plasma treatment process results in a mono layer of Si—N bonds to be formed.
9. A method comprising:
performing a thermal soaking process using a silicon-containing gas to deposit a silicon layer on a surface of an underlying layer;
performing a plasma treatment process on the silicon layer to form a silicon-and-nitrogen-containing layer; and
depositing a metallic layer on the silicon-and-nitrogen-containing layer, wherein the plasma treatment process and the depositing the metallic layer are in-situ performed in a same process chamber without vacuum break therebetween.
10. The method of claim 9 , wherein the silicon layer is deposited as a mono layer.
11. The method of claim 9 , wherein the metallic layer and the silicon-and-nitrogen-containing layer form a SiN layer, and the SiN layer forms a bond with metal atoms in the metallic layer.
12. The method of claim 9 , wherein the underlying layer comprises an inter-layer dielectric and a source/drain silicide region, and the silicon layer is formed on both of the inter-layer dielectric and the source/drain silicide region.
13. The method of claim 9 , wherein the plasma treatment process is performed using hydrogen (H 2 ) and nitrogen (N 2 ) as process gases.
14. The method of claim 9 , wherein there is no vacuum break occurring between the thermal soaking process and the depositing the metallic layer.
15. The method of claim 9 , wherein the depositing the metallic layer comprises a plating process.
16. A method comprising:
forming a silicide region;
depositing a silicon layer over the silicide region;
performing a treatment process on the silicon layer using hydrogen (H 2 ) and a nitrogen-containing gas to generate a silicon-and-nitrogen containing layer, wherein at a time the treatment process is finished, the silicon-and-nitrogen containing layer is free from metal therein; and
depositing a cobalt layer over and contacting the silicon-and-nitrogen containing layer.
17. The method of claim 16 , wherein the depositing the silicon layer comprises thermally soaking the silicide region in a silicon-containing process gas.
18. The method of claim 17 , wherein the depositing the silicon layer comprises thermally soaking the silicide region in silane.
19. The method of claim 16 , wherein the treatment process comprises a plasma treatment process.
20. The method of claim 16 , wherein the cobalt layer forms bonds with the silicon-and-nitrogen containing layer that is free from metal therein.