Methods of forming ferroelectric capacitors
A method of forming a ferroelectric capacitor includes forming inner conductive capacitor electrode material over a substrate. After forming the inner electrode material, an outermost region of the inner electrode material is treated to increase carbon content in the outermost region from what it was prior to the treating. After the treating, ferroelectric capacitor dielectric material is formed over the treated outermost region of the inner electrode material. Outer conductive capacitor electrode material is formed over the ferroelectric capacitor dielectric material.
1. A method of forming a ferroelectric capacitor, comprising:
forming inner conductive capacitor electrode material over a substrate;
after forming the inner electrode material, treating an outermost region of the inner electrode material to increase carbon content in the outermost region from what it was prior to the treating;
after the treating, forming ferroelectric capacitor dielectric material over the treated outermost region of the inner electrode material; and
forming outer conductive capacitor electrode material over the ferroelectric capacitor dielectric material.
2. The method of claim 1 wherein carbon content in the outermost region is about 0.01 atomic percent to about 10 atomic percent after the treating.
3. The method of claim 2 wherein carbon content in the outermost region after the treating is about 1 atomic percent to about 5 atomic percent.
4. The method of claim 1 comprising an innermost region of the inner electrode material inward of the outermost region which extends to an innermost surface of the inner electrode material, the innermost region having carbon content of at least about 0.01 atomic percent before and after the treating.
5. The method of claim 1 comprising an innermost region of the inner electrode material inward of the outermost region which extends to an innermost surface of the inner electrode material, the innermost region being devoid of carbon before and after the treating.
6. The method of claim 1 wherein the inner electrode material is metallic and which is directly against substrate material that is devoid of metal.
7. The method of claim 6 comprising an innermost region of the inner electrode material inward of the outermost region which extends to the substrate material, the outermost region having a maximum thickness that is less than that of the innermost region.
8. The method of claim 1 wherein the outermost region is homogenous at least regarding carbon content after the treating.
9. The method of claim 1 wherein the outermost region is not homogenous at least regarding carbon content after the treating.
10. The method of claim 9 wherein an outermost part of the outermost region has greater carbon content than an innermost part of the outermost region after the treating.
11. The method of claim 9 wherein a region of greatest carbon concentration in the outermost region is displaced inwardly from an outermost surface of the outermost region after the treating, the outermost region having a thickness no greater than 20 Angstroms.
12. The method of claim 11 wherein the inner electrode material has a maximum thickness of no greater than about 300 Angstroms.
13. The method of claim 1 wherein the treating comprises ion implanting carbon material.
14. The method of claim 13 wherein the ion implanting comprises plasma.
15. The method of claim 14 wherein the treating comprises plasma immersion ion implantation.
16. The method of claim 1 wherein the treating comprises diffusion of carbon material into and through an outermost surface of the outermost region.
17. The method of claim 16 wherein the treating comprises gas phase diffusion.
18. The method of claim 16 wherein the carbon material is in plasma phase over the outermost surface during the diffusion.
19. The method of claim 1 wherein the ferroelectric capacitor dielectric material comprises one of more of transition metal oxide, zirconium, zirconium oxide, hafnium, hafnium oxide, lead zirconium titanate, tantalum oxide, and barium strontium titanate, and having dopant therein which comprises one or more of silicon, aluminum, lanthanum, yttrium, erbium, calcium, magnesium, strontium, and a rare earth element.
20. The method of claim 19 wherein forming the ferroelectric capacitor dielectric material comprises depositing an initially amorphous phase solid followed by crystalline phase transformation of the amorphous phase solid after its deposition.
21. The method of claim 19 wherein the inner electrode material comprises TiN.
22. The method of claim 1 comprising forming the ferroelectric capacitor dielectric material directly against the outermost region.
23. The method of claim 22 being devoid of forming any non-ferroelectric dielectric oxide between any of the outermost region and the ferroelectric capacitor dielectric material.
24. The method of claim 1 comprising forming at least one of a non-ferroelectric dielectric oxide, a non-ferroelectric dielectric oxynitride, and a non-ferroelectric dielectric carbon oxynitride between at least some of the outermost region and the ferroelectric capacitor dielectric material.
25. The method of claim 24 comprising forming another some of the outermost region and the ferroelectric capacitor dielectric material directly against one another.
26. The method of claim 1 comprising forming the outermost region to comprise oxygen at least after forming the ferroelectric capacitor dielectric material.
27. The method of claim 1 comprising forming the outermost region to be devoid of oxygen at least after forming the ferroelectric capacitor dielectric material.
28. The method of claim 1 comprising forming the outermost region to a maximum thickness of about 5 to 20 Angstroms.
29. The method of claim 28 comprising forming the inner electrode material to a maximum thickness of no greater than about 300 Angstroms.
30. The method of claim 1 comprising incorporating the ferroelectric capacitor in a ferroelectric random access memory cell.