Fabricating correlated electron material (CEM) devices
Subject matter disclosed herein may relate to construction of a correlated electron material (CEM) device. In particular embodiments, after formation of a film comprising layers of a transition metal oxide (TMO) material and a dopant, at least a portion of the film may be exposed to an elevated temperature. Exposure of the at least a portion of the film to the elevated temperature may continue until the atomic concentration of the dopant within the film is reduced, which may enable operation of the film as a correlated electron material CEM exhibiting switching of impedance states.
1. A method of constructing a correlated electron material (OEM) device, comprising:
forming one or more layers of a transition metal oxide (TMO) material over a substrate, the one or more layers of the TMO material comprising a first atomic concentration of an extrinsic ligand; and
exposing at least a first portion of the one or more layers of the TMO material formed over the substrate, in a chamber, to an elevated temperature without exposing at least a second portion of the one or more layers of the TMO material to the elevated temperature until at least the first portion of the one or more layers of the TMO material comprises no greater than a second atomic concentration of the extrinsic ligand to render the first portion of the one or more layers of the TMO material capable of switching between a relatively conductive state and a substantially dissimilar insulative state without rendering the second portion of the one or more layers of the TMO material capable of switching between the relatively conductive state and the substantially dissimilar insulative state.
2. The method of claim 1 , wherein the second atomic concentration of the extrinsic ligand is less than the first atomic concentration of the extrinsic ligand.
3. The method of claim 1 , wherein the extrinsic ligand provides a dopant to enable the low-impedance or conductive slate of the at least the first portion of the one or more layers of the TMO material.
4. The method of claim 3 , wherein the dopant comprises carbon, carbonyl (CO), nitric oxide (NO), or ammonia (NH3).
5. The method of claim 1 , further comprising forming a conductive overlay over the one or more layers of TMO material prior to exposing the at least the first portion of the one or more layers of the TMO material formed over the substrate to the elevated temperature.
6. The method of claim 5 , wherein the exposing the at least the first portion of the one or more layers of the TMO material to the elevated temperature comprises exposing the at least the first portion of the one or more layers of the TMO material to the elevated temperature at least until a conductive oxide layer is formed at an interface between the substrate and the TMO material.
7. The method of claim 6 , wherein the conductive oxide layer comprises a sub-monolayer of the conductive oxide, a monolayer of the conductive oxide, or a plurality of layers of the conductive oxide.
8. The method of claim 6 , wherein the substrate comprises at least 50.0% atomic concentration of iridium, and wherein the conductive oxide layer comprises iridium oxide.
9. The method of claim 6 , wherein the substrate comprises at least 50.0% atomic concentration of ruthenium, and wherein the conductive oxide layer comprises ruthenium oxide.
10. The method of claim 1 , wherein the second atomic concentration comprises an atomic concentration of the extrinsic ligand in the at least the first portion of the one or more layers of the TMO material of about 0.1% to about 15.0%.
11. The method of claim 1 , wherein the elevated temperature comprises a range of between about 900° C. to about 1500° C., and wherein the at least the first portion of the one or more layers of the TMO material is exposed to the elevated temperature for a duration of about 0.5 μs to about 2.0 μs or for a duration of about 250 μs to about 2.0 seconds.
12. The method of claim 1 , wherein the elevated temperature is achieved, at least in part, via one or more laser pulses having a duration of between 0.5 μs and 2.0 μs to provide a temperature equal to about 900.0° C. to about 1500.0° C. at the at least the first portion of the one or more layers of the TMO material.
13. The method of claim 1 , wherein the elevated temperature is achieved, at least in part, utilizing one or more pulses of a flashlamp for duration of between about 250.0 μs and about 2.0 seconds to provide a temperature equal to about 900.0° C. to about 1500.0° C. at the at least the first portion of the one or more layers of the TMO material.
14. The method of claim 1 , wherein the first atomic concentration of the extrinsic ligand in the one or more layers of TMO material comprises an atomic concentration of between about 0.1% and about 50.0%.
15. A method of fabricating a correlated electron material (CEM) device, comprising:
forming a film of a transition metal oxide (TMO) material over a substrate, the TMO material comprising an atomic concentration of an extrinsic ligand; and
exposing at least a first portion of the film of the TMO material, in a chamber, to an elevated temperature without exposing at least a second portion of the film of TMO material to the elevated temperature to reduce the atomic concentration of the extrinsic ligand in the at least the first portion of the film of TMO material until the at least the first portion of the film of the TMO material is capable of switching between a conductive state and a substantially dissimilar insulative state while maintaining the second portion of the film of TMO material incapable of switching between the conductive state and the substantially dissimilar state insulative state.
16. The method of claim 15 , wherein the at least the first portion of the film of the TMO material, operating in the substantially dissimilar insulative state, exhibits a resistance at least 5.0 times a resistance exhibited in the conductive slate.
17. The method of claim 15 , wherein the extrinsic ligand corresponds to carbon, carbonyl (CO), nitric oxide (NO), or ammonia (NH3).
18. The method of claim 15 , further comprising forming a conductive overlay over the film of TMO material prior to exposing the at least the first portion of the film of TMO material to the elevated temperature.
19. The method of claim 15 , wherein the substrate comprises at least 50.0% atomic concentration of iridium or at least 50.0% atomic concentration of ruthenium, and wherein the exposing acts to form at least a submonolayer of iridium oxide or ruthenium oxide at an interface between the film of the TMO material and the substrate.
20. The method of claim 15 , wherein the film of the TMO material comprises a conductive attribute.
21. The method of claim 15 , wherein the elevated temperature comprises a range of between about 900° C. to about 1500° C., and wherein the at least the first portion of the film of the TMO material is exposed to the elevated temperature for a duration of about 0.5 μs to about 2.0 μs or for a duration of about 250 μs to about 2.0 seconds.
22. The method of claim 15 , wherein the elevated temperature is achieved, at least in part, via one or more laser pulses having a duration of between 0.5 μs and 2.0 μs to provide a temperature of between about 900.0° C. to about 1500.0° C. at the at least the first portion of the film of the TMO material.
23. The method of claim 15 , wherein the elevated temperature is achieved, at least in part, via one or more pulses of a flashlamp having a duration of between about 250.0 μs and about 2.0 seconds to provide a temperature of between about 900.0° C. to about 1500.0° C. at the at least the first portion of the film of the TMO material.
24. The method of claim 15 , wherein the atomic concentration of the extrinsic ligand in the film of the TMO material prior to the exposing the at least the first portion of the film of the TMO material to the elevated temperature comprises between about 0.1% and about 50.0%.
25. A method of fabricating a correlated electron material (CEM) device, comprising:
forming a film of a transition metal oxide (TMO) material over a substrate, the film of the TMO material comprising a first atomic concentration of an extrinsic ligand; and
evaporating, in a chamber, a portion of the extrinsic ligand from at least a first portion of the film of the TMO material until the at least the first portion of the film of the TMO material is capable of switching between a relatively conductive state and a substantially dissimilar insulative state while maintaining at least a second portion of the film of the TMO material incapable of switching between the relatively conductive state and the substantially dissimilar state.
26. The method of claim 25 , wherein the evaporating the portion of the extrinsic ligand from the at least the first portion of the film of the TMO material comprises exposing the at least the first portion of the film of the TMO material to a temperature of between about 900° C. to about 1500° C. for a duration of between about 0.5 μs and about 2.0 μs or for a duration of about 250 μs to about 2.0 seconds.
27. The method of claim 25 , wherein the evaporating the portion of the extrinsic ligand from the at least the first portion of the film of the TMO material comprises exposing the at least the first portion of the film of the TMO material to one or more laser pulses having a duration of between 0.5 μs and 2.0 μs to provide a temperature between about 900.0° C. to about 1500.0° C. at the at least the first portion of the portion of the film of the TMO material.
28. The method of claim 25 wherein the evaporating the portion of the extrinsic ligand from the at least the first portion of the film of the TMO material comprises exposing the at least the first portion of the film of the TMO material utilizing one or more flashes of a flashlamp of between about 250.0 μs to about 2.0 seconds to provide a temperature of between about 900.0° C. to about 1500.0° C. at the at least the first portion of the film of the TMO material.