Nonvolatile memory device using a tunnel oxide as a passive current steering element
View Patent ↗Embodiments of the invention generally include a method of forming a nonvolatile memory device that contains a resistive switching memory element that has improved device switching performance and lifetime, due to the addition of a current limiting component disposed therein. The electrical properties of the current limiting component are configured to lower the current flow through the variable resistance layer during the logic state programming steps by adding a fixed series resistance in the resistive switching memory element of the nonvolatile memory device. In one embodiment, the current limiting component comprises a tunnel oxide that is a current limiting material disposed within a resistive switching memory element in a nonvolatile resistive switching memory device. Typically, resistive switching memory elements may be formed as part of a high-capacity nonvolatile memory integrated circuit, which can be used in various electronic devices, such as digital cameras, mobile telephones, handheld computers, and music players.
1. A nonvolatile memory element comprising:
a variable resistance layer comprising a metal oxide;
a current limiting layer disposed adjacent the variable resistance layer;
a separation layer disposed between the current limiting layer and the variable resistance layer, wherein the separation layer comprises a conductor material resistant to oxygen diffusion;
a first stabilizing layer disposed adjacent the current limiting layer, the first stabilizing layer operable to provide oxygen to the current limiting layer; and
a second stabilizing layer disposed adjacent the current limiting layer, the second stabilizing layer operable to provide oxygen to the current limiting layer,
wherein the first stabilizing layer and the second stabilizing layer each comprise a material selected from the group consisting of indium tin oxide, iridium oxide and indium zinc oxide.
2. The nonvolatile memory element of claim 1 , wherein the variable resistance layer comprises a material selected from the group of hafnium oxide, zirconium oxide, lanthanum oxide, and aluminum oxide.
3. The nonvolatile memory element of claim 1 , wherein the current limiting layer comprises a material selected from the group of aluminum oxide, zirconium oxide, silicon oxide, and silicon nitride.
4. The nonvolatile memory element of claim 1 , wherein the separation layer comprises a material selected from the group of tantalum nitride, titanium nitride and tungsten nitride, silicon oxy-nitride, aluminum oxy-nitride, aluminum nitride, hafnium nitride zirconium nitride, boron nitride, calcium nitride, ruthenium titanium nitride, gold, zirconium platinum and platinum beryllium.
5. The nonvolatile memory element of claim 1 , wherein the current limiting layer is a tunnel oxide that has a thickness of between 20 angstroms and 100 angstroms.
6. A nonvolatile memory element comprising:
a variable resistance layer comprising a metal oxide;
a current limiting layer disposed adjacent the variable resistance layer, the current limiting layer comprising a tunnel oxide;
a separation layer disposed between the current limiting layer and the variable resistance layer, the separation layer operable to inhibit the flow of oxygen ions from the variable resistance layer;
a first stabilizing layer disposed adjacent the current limiting layer, the first stabilizing layer operable to provide oxygen to the current limiting layer; and
a second stabilizing layer disposed adjacent the current limiting layer, the second stabilizing layer operable to provide oxygen to the current limiting layer,
wherein the first stabilizing layer and the second stabilizing layer each comprise a material selected from the group consisting of indium tin oxide, iridium oxide and indium zinc oxide.
7. The nonvolatile memory element of claim 6 , wherein the variable resistance layer comprises a material selected from the group of hafnium oxide, zirconium oxide, lanthanum oxide and aluminum oxide.
8. The nonvolatile memory element of claim 6 , wherein the current limiting layer comprises a material selected from the group of aluminum oxide, zirconium oxide, silicon oxide and silicon nitride.
9. The nonvolatile memory element of claim 6 , wherein the first stabilizing layer and second stabilizing layer each have a thickness of between 50 angstroms and 1000 angstroms.
10. The nonvolatile memory element of claim 6 , wherein each of the first stabilizing layer and second stabilizing layer comprise a material selected from the group of indium tin oxide and iridium oxide, and wherein the materials selected for each first stabilizing layer and second stabilizing layer are not the same.
11. The nonvolatile memory element of claim 6 , wherein the separation layer comprises a material selected from the group of tantalum nitride, titanium nitride, tungsten nitride, silicon oxy nitride, aluminum oxy-nitride, aluminum nitride, hafnium nitride zirconium nitride, gold, zirconium, platinum and platinum beryllium.
12. The nonvolatile memory element of claim 6 , wherein the separation layer has a thickness of between 30 angstroms and 1000 angstroms.
13. A method of forming a nonvolatile memory element, comprising:
forming a variable resistance layer comprising a metal oxide;
forming a current limiting layer disposed adjacent the variable resistance layer;
forming a separation layer disposed between the current limiting layer and the variable resistance layer, wherein the separation layer is operable to prevent mobile oxygen atoms in the current limiting layer from passing to the variable resistance layer;
forming a first stabilizing layer disposed adjacent the current limiting layer, the first stabilizing layer operable to provide oxygen to the current limiting layer; and
forming a second stabilizing layer disposed adjacent the current limiting layer, the second stabilizing layer operable to provide oxygen to the current limiting layer,
wherein the first stabilizing layer and the second stabilizing layer each comprise a material selected from the group consisting of indium tin oxide, iridium oxide and indium zinc oxide.
14. The method of claim 13 , wherein the separation layer comprises a material selected from the group of tantalum nitride, titanium nitride and tungsten nitride, silicon oxy-nitride, aluminum oxy-nitride, aluminum nitride, hafnium nitride zirconium nitride, gold, zirconium platinum and platinum beryllium.
15. The method of claim 13 , wherein the current limiting layer comprises a material selected from the group of aluminum oxide, zirconium oxide, silicon oxide, and silicon nitride.