Interfacial oxide used as switching layer in a nonvolatile resistive memory element
A nonvolatile resistive memory element includes a host oxide formed from an interfacial oxide layer. The interfacial oxide layer is formed on the surface of a deposited electrode layer via in situ or post-deposition surface oxidation treatments.
1. A method of forming a nonvolatile memory element, the method comprising:
forming a first layer operable as an electrode layer of the nonvolatile memory element;
forming a variable resistance layer comprising an interfacial oxide layer on a surface of the first layer by treating the surface of the first layer with an oxidation treatment,
wherein the interfacial oxide layer formed by the oxidation treatment,
wherein the interfacial oxide layer comprises a metal oxide containing layer,
wherein the metal oxide containing layer has a thickness of less than 20 angstroms,
treating the interfacial oxide layer; and
after treating the interfacial oxide layer, depositing a second layer above the interfacial oxide layer,
wherein the second layer is operable as an electrode layer of the nonvolatile memory element.
2. The method of claim 1 , wherein the oxidation treatment comprises a process from the group consisting of a wet oxidation process, exposing the surface to ozone (O 3 ), and exposing the surface to an oxygen-containing atmosphere under controlled conditions for a predetermined time period.
3. The method of claim 2 , wherein the wet oxidation process comprises an SC-1 process.
4. The method of claim 1 , further comprising removing a native oxide layer from the surface prior to forming the interfacial oxide layer on the surface.
5. The method of claim 4 , wherein removing the native oxide layer from the surface comprises one of the group of processes consisting of plasma etching the native oxide layer, exposing the native oxide layer to a hydrofluoric acid containing vapor, and applying a hydrofluoric acid containing solution to the surface.
6. The method of claim 1 , wherein treating the interfacial oxide layer comprises one of the group of processes consisting of rapid thermal processing, decoupled plasma nitridization, exposing the interfacial oxide layer to an ammonia (NH 3 ) containing solution, exposing the interfacial oxide layer to a nitrogen plasma, exposing the interfacial oxide layer to an oxygen plasma, and exposing the interfacial oxide layer to an ozone soak in an atomic layer deposition chamber.
7. The method of claim 1 , further comprising thermally annealing the first layer, the second layer, and the interfacial oxide layer after depositing the second layer.
8. The method of claim 1 , wherein the second layer is formed adjacent to the interfacial oxide layer and comprises a chemical element from the group consisting of tantalum (Ta), titanium (Ti), and nitrogen (N).
9. The method of claim 1 , wherein the metal oxide containing layer comprises a material from the group consisting of TiOx, TiSiOx, TaOx, TaSiOx, and a combination thereof.
10. The method of claim 1 , wherein the variable resistance layer of the nonvolatile memory element is configured to be switched between two or more resistive states.
11. The method of claim 1 , wherein the first layer comprises titanium nitride.
12. The method of claim 1 , wherein the first layer comprises one of titanium nitride, tantalum nitride, titanium, tantalum, or a transition metal alloy.
13. The method of claim 7 , wherein thermally annealing of the first layer, the second layer, and the interfacial oxide layer after depositing the second layer comprises transferring one or more chemical elements from the second layer into the interfacial oxide layer.
14. The method of claim 13 , wherein the one or more chemical elements comprises at least one of titanium, tantalum, or nitrogen.
15. The method of claim 1 , wherein the oxidation treatment comprises exposing the surface of the first layer to atmospheric air.
16. The method of claim 1 , wherein treating the interfacial oxide layer comprises decoupled plasma nitridization.
17. The method of claim 1 , wherein treating the interfacial oxide layer comprises exposing the interfacial oxide layer to an ammonia (NH 3 ) containing solution.
18. The method of claim 1 , wherein treating the interfacial oxide layer generates additional oxygen vacancies in the interfacial oxide layer.
19. The method of claim 1 , wherein the second layer directly interfaces the interfacial oxide layer.
20. The method of claim 1 , wherein a thickness of the interfacial oxide layer is controlled by controlled by controlling temperature, oxygen concentration, and duration of the oxidation treatment.