Nonvolatile memory device using a tunnel oxide as a current limiter element
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 first layer operable as an electrode;
a second layer operable as an electrode;
a third layer operable as a variable resistance layer disposed between the first layer and the second layer, the third layer comprising a metal oxide;
a fourth layer operable as a current limiting layer disposed between the third layer and the first layer; and
a fifth layer comprising an oxygen deficient material disposed between the fourth layer and the third layer, wherein
the fifth 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.
2. The nonvolatile memory element of claim 1 , wherein the third 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 third layer has a thickness of between 20 angstroms and 100 angstroms.
4. The nonvolatile memory element of claim 1 , wherein the fourth layer comprises a material selected from the group of aluminum oxide, zirconium oxide, silicon oxide, and silicon nitride.
5. The nonvolatile memory element of claim 1 , wherein the fourth layer has a thickness of between 20 angstroms and 500 angstroms.
6. The nonvolatile memory element of claim 1 , wherein the fourth layer is a tunnel oxide that has a thickness of between 20 angstroms and 100 angstroms.
7. A nonvolatile memory element, comprising a first layer operable as an electrode; a second layer operable as an electrode; a third layer operable as variable resistance layer disposed between the first layer and the second layer, the third layer comprising a metal oxide; a fourth layer operable as a current limiting layer disposed between the first layer and the third layer, the fourth layer comprising a tunnel oxide; a fifth layer disposed between the fourth layer and the third layer, the fifth layer operable to inhibit oxygen from the variable resistance layer; a sixth layer operable to provide oxygen to the current limiting layer; and a seventh layer operable to provide oxygen to the current limiting layer, wherein the fourth layer is disposed between the sixth layer and the seventh layer, wherein
the fifth 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.
8. The nonvolatile memory element of claim 7 , wherein the third layer comprises a material selected from the group of hafnium oxide, zirconium oxide, lanthanum oxide and aluminum oxide.
9. The nonvolatile memory element of claim 7 , wherein the third layer has a thickness of between 20 angstroms and 100 angstroms.
10. The nonvolatile memory element of claim 7 , wherein the fourth layer comprises a material selected from the group of aluminum oxide, zirconium oxide, silicon oxide and silicon nitride.
11. The nonvolatile memory element of claim 7 , wherein the fourth layer has a thickness of between 20 angstroms and 500 angstroms.
12. The nonvolatile memory element of claim 7 , wherein the fifth layer has a thickness of between 30 angstroms and 1000 angstroms.
13. The nonvolatile memory element of claim 7 , wherein the sixth layer and the seventh layer each comprise a material selected from the group consisting of indium tin oxide and iridium oxide and indium zinc oxide.
14. The nonvolatile memory element of claim 7 , wherein the sixth layer and seventh layer each have a thickness of between 50 angstroms and 1000 angstroms.
15. The nonvolatile memory element of claim 13 , wherein each of the sixth layer and the seventh layer comprise a material selected from the group of indium tin oxide and iridium oxide, and wherein the materials selected for each sixth layer and seventh layer are not the same.
16. A method of forming a nonvolatile memory element, comprising: forming a first electrode layer comprising a first electrode material over a surface of a substrate; forming a second electrode layer comprising a second electrode material; forming a variable resistance layer comprising a metal oxide, wherein the variable resistance layer is disposed between the first electrode layer and the second electrode layer; forming a current limiting layer, wherein the current limiting layer is disposed between the first electrode layer and the variable resistance layer; and forming a separation layer comprising an oxygen deficient material, wherein the separation layer is disposed between the current limiting layer and the variable resistance layer, 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.
17. The method of claim 16 , wherein the current limiting layer comprises a material selected from the group of aluminum oxide, zirconium oxide, silicon oxide, and silicon nitride.