Nonvolatile memory device and fabrication method thereof
View Patent ↗A nonvolatile memory device and its fabrication method of the present invention may ensure a margin of the threshold drive voltage during a design process of the device by forming a resistance layer determining phase of ReRAM along an upper edge of a lower electrode, and improve operating characteristics of the device.
1. A nonvolatile memory device, comprising:
a first electrode;
a first resistance layer formed along an edge of the first electrode;
a second resistance layer filled inside the first resistance layer; and
a second electrode formed over the first and second resistance layers;
wherein the material forming the second resistance layer has a threshold drive voltage for switching phase higher than the threshold drive voltage for switching phase of the material forming the first resistance layer.
2. The nonvolatile memory device of claim 1 , wherein the first electrode and the second electrode comprise platinum group elements.
3. The nonvolatile memory device of claim 2 , wherein the platinum group elements are selected from the group consisting of platinum (Pt), iridium (Ir) and metallurgical equivalents of platinum and iridium.
4. The nonvolatile memory device of claim 1 , wherein the first resistance layer comprises an oxide containing niobium (Nb).
5. The nonvolatile memory device of claim 4 , wherein the oxide containing Nb consists mainly of NbO 2 or Nb 2 O 5 .
6. The nonvolatile memory device of claim 1 , wherein the second resistance layer comprises an oxide containing aluminum (Al).
7. The nonvolatile memory device of claim 6 , wherein the oxide containing Al consists mainly of Al 2 O 3 .
8. The nonvolatile memory device of claim 1 , wherein the first resistance layer is formed over an upper edge of the first electrode.