CEM switching device
Subject matter herein disclosed relates to an improved CEM switching device and methods for its manufacture. In this device, a conductive substrate and/or conductive overlay comprises a primary layer of a conductive material and a secondary layer of a conductive material. The primary layer contacting the CEM layer is substantially inert to the CEM layer and/or acts as an oxygen barrier for the secondary layer at temperatures used for the manufacture of the device.
1. A method for the manufacture of a CEM switching device, which method comprises forming a conductive substrate, forming a layer of a correlated electron material (CEM) on the conductive substrate and forming a conductive overlay on the CEM layer, wherein the forming the conductive overlay comprises forming a primary layer of a conductive material contacting the CEM layer and forming a secondary layer of a conductive material on or over the primary layer and the forming of the conductive substrate comprises forming a secondary layer of a conductive material on a substrate and forming a primary layer of a conductive material on the secondary layer wherein the thickness of the secondary layer is greater than that of the primary layer and wherein the conductive material of the primary layer is substantially resistant to diffusion or migration of oxygen ion from the CEM layer to the secondary layer.
2. The method according to claim 1 , wherein the conductive material of the primary layer is substantially resistant to diffusion or migration of oxygen ion at temperatures between 20° C. and 1000° C.
3. The method according to claim 1 , wherein the conductive material of the primary layer is substantially resistant to diffusion or migration of oxygen ion at temperatures between 20° C. and 750° C.
4. The method according to claim 1 , wherein the conductive material of the primary layer is substantially resistant to diffusion or migration of oxygen ion at temperatures between 20° C. and 450° C.
5. The method according to claim 1 , wherein the conductive material of the primary layer is resistant to oxidation by the CEM layer.
6. The method according to claim 1 , wherein the CEM layer comprises one or more of a d- or f-block metal oxide.
7. The A method according to claim 1 , wherein the conductive material of the secondary layer is susceptible to oxidation by the CEM layer.
8. The method according to claim 7 , wherein the conductive material of the secondary layer comprises one or more of copper, cobalt, aluminum, nickel, titanium, tantalum, tungsten, titanium nitride, tantalum nitride, tungsten nitride, a silicide, and polysilicon.
9. The method according to claim 1 , wherein the conductive material of the primary layer comprises one or more of a noble metal or a noble metal oxide.
10. A switching device comprising a conductive substrate, a conductive overlay and a layer of a correlated electron material (CEM) therebetween wherein the conductive substrate and the conductive overlay each comprises a primary layer of a conductive material and a secondary layer of a conductive material wherein the thickness of the secondary layer is greater than that of the primary layer and wherein the primary layer contacts the CEM layer and is substantially resistant to diffusion or migration of oxygen ion from the CEM layer to the secondary layer.
11. The switching device according to claim 10 , wherein the conductive material of the primary layer comprises one or more of a noble metal or a noble metal oxide.
12. The switching device according to claim 10 , wherein the conductive material of the secondary layer is susceptible to oxidation by the CEM layer.
13. The switching device according to claim 11 , wherein the one or more noble metal is selected from the group consisting of platinum, palladium, rhodium, ruthenium and iridium.
14. The switching device according to claim 12 , wherein the conductive material of the secondary layer comprises one or more of copper, cobalt, aluminum, nickel, titanium, tantalum, tungsten, titanium nitride, tantalum nitride, tungsten nitride, a metal silicide and polysilicon.