Deposition of tungsten on molybdenum templates
Provided herein are low resistance metallization stack structures for logic and memory applications and related methods of fabrication. The methods involve forming bulk conductive films on thin low resistivity transition metal layers that have large grain size. The bulk conductive films follow the grains of the low resistivity transition metal films, resulting in large grain size. Also provided are devices including template layers and bulk films.
1. A method comprising:
depositing a molybdenum (Mo)-containing layer in a feature on a substrate; and
depositing tungsten (W) on the Mo-containing layer to thereby fill the feature with tungsten, wherein the average crystallite size of the tungsten is at least 20 nm.
2. The method of claim 1 , further comprising thermally annealing the Mo-containing layer prior to depositing tungsten.
3. The method of claim 1 , wherein the Mo-containing layer is a template for W grain growth.
4. The method of claim 1 , wherein the Mo-containing layer is elemental Mo having less than 1 (atomic) % impurities.
5. The method of claim 1 , wherein the Mo-containing layer is between 1 and 10 nm thick.
6. The method of claim 1 , wherein the Mo-containing layer overlies a dielectric layer.
7. The method of claim 1 , wherein the Mo-containing layer is free of fluorine impurities.
8. The method of claim 1 , further comprising depositing the Mo-containing layer.
9. The method of claim 8 , wherein the Mo-containing layer is deposited from one or more molybdenum chloride precursors.
10. The method of claim 9 , wherein the one or more molybdenum chloride precursors are selected from: molybdenum pentachloride (MoCl 5 ), molybdenum dichloride dioxide (MoO 2 Cl 2 ), and molybdenum tetrachloride oxide (MoOCl 4 ).
11. The method of claim 8 , wherein depositing the Mo-containing layer comprises performing an atomic layer deposition process in which a molybdenum chloride precursor is reduced by hydrogen.
12. The method of claim 1 , wherein the tungsten is deposited using tungsten hexafluoride.
13. The method of claim 1 , wherein the average crystallite size of the Mo-containing layer is at least 20 nm.
14. The method of claim 1 , wherein the tungsten is deposited without depositing a nucleation layer.
15. The method of claim 1 , wherein is tungsten deposited by atomic layer deposition (ALD).
16. The method of claim 1 , wherein the feature is one of a plurality of wordline features of a 3-D memory structure, the 3-D memory structure comprising sidewalls, a plurality of openings in the sidewalls leading to the plurality of features having a plurality of interior regions fluidically accessible through the openings, wherein the Mo-containing layer is deposited to conformally line the plurality of wordline features and the tungsten fills the plurality of wordline features.
17. The method of claim 1 , wherein the Mo-containing layer is deposited from molybdenum hexafluoride (MoF 6 ).
18. A method comprising:
forming a conductive molybdenum template layer on a substrate, the conductive molybdenum template layer being between 1 and 5 nm thick;
annealing the conductive molybdenum template layer to increase grain size within the conductive molybdenum template layer; and
forming a bulk conductive layer on the conductive molybdenum template layer, wherein grains in the bulk conductive layer follow those of the conductive molybdenum template layer.
19. The method of claim 18 , wherein the conductive molybdenum template layer is free of fluorine impurities.
20. The method of claim 18 , wherein forming the conductive molybdenum template layer comprises depositing the molybdenum template layer using one or more molybdenum chloride precursors.
21. The method of claim 20 , wherein the one or more molybdenum chloride precursors are selected from: molybdenum pentachloride (MoCl 5 ), molybdenum dichloride dioxide (MoO 2 Cl 2 ), and molybdenum tetrachloride oxide (MoOCl 4 ).
22. The method of claim 18 , wherein forming the conductive molybdenum template layer comprises depositing the conductive molybdenum template layer using molybdenum hexafluoride (MoF 6 ).
23. The method of claim 18 , wherein depositing the conductive molybdenum template layer comprises performing an atomic layer deposition process in which a molybdenum-containing precursor is reduced by hydrogen.
24. The method of claim 18 , wherein the bulk conductive layer is selected from the group consisting of tungsten, cobalt, ruthenium, nickel, and alloys containing at least one of tungsten, cobalt, ruthenium, nickel.
25. A method comprising:
providing a partially fabricated 3-D NAND structure having multiple oxide layers separated by gaps; and
conformally depositing a molybdenum template layer in the gaps, wherein the molybdenum template layer is deposited directly on an oxide surface.
26. The method of claim 25 , wherein the molybdenum template layer is between about 1 and 10 nm thick.
27. The method of claim 25 , wherein the molybdenum template layer is between 1 and 5 nm thick.
28. The method of claim 25 , further comprising filling the gaps with tungsten.