Nonvolatile metal oxide memory element and nonvolatile memory device
According to one embodiment, a nonvolatile memory device includes a plurality of nonvolatile memory elements each of that includes a resistance change film. The resistance change film is capable of recording information by transitioning between a plurality of states having different resistances in response to at least one of a voltage applied to the resistance change film or a current passed through the resistance change film, and the resistance change film includes an oxide containing at least one element selected from the group consisting of Hf, Zr, Ni, Ta, W, Co, Al, Fe, Mn, Cr, and Nb. An impurity element contained in the resistance change film is at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Sc, Y, La, V, Ta, B, Ga, In, Tl, C, Si, Ge, Sn, Pb, N, P, As, Sb, Bi, S, Se, and Te, and the impurity element has an absolute value of standard Gibbs energy of oxide formation larger than an absolute value of standard Gibbs energy of oxide formation of the element contained in the oxide.
1. A nonvolatile memory element comprising:
an anode electrode;
a cathode electrode;
a resistance change film provided between the anode electrode and the cathode electrode, and capable of recording information by transitioning between a plurality of states having different resistances in response to at least one of a voltage applied to the resistance change film or a current passed through the resistance change film, the resistance change film including an oxide containing at least one element selected from the group consisting of Hf, Zr, Ni, Ta, W, Co, Al, Fe, Mn, Cr, and Nb; and
an impurity element contained in the resistance change film being at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Sc, Y, La, V, Ta, B, Ga, In, TI, C, Si, Ge, Sn, Pb, N, P, As, Sb, Bi, S, Se, and Te, the impurity element having an atomic radius larger than an atomic radius of the element contained in the oxide, and a doping amount of the impurity element being 1×10 14 cm −2 or more,
wherein a set voltage of the resistance change film is smaller than a reset voltage of the resistance change film, the set voltage changing a state of the resistance change film from a high resistance state to a low resistance state, and the reset voltage changing a state of the resistance change film from the low resistance state to the high resistance state.
2. The element according to claim 1 , wherein the resistance change film includes an impurity doping region doped with the impurity element.
3. The element according to claim 2 , wherein the impurity doping region is provided in a central portion of the resistance change film.
4. The element according to claim 1 , wherein the impurity element is different in valence from the element contained in the oxide.
5. The element according to claim 1 , wherein the impurity element is lower in covalency than the element contained in the oxide.
6. The element according to claim 1 , wherein the oxide is a binary oxide represented by M x O y (M: metal, O: oxygen).
7. The element according to claim 1 , wherein the oxide is a ternary metal oxide represented by A α M β O γ (A, M: metals, O: oxygen).
8. A nonvolatile memory device comprising:
a plurality of the nonvolatile memory elements, each of the nonvolatile memory elements comprising:
an anode electrode;
a cathode electrode
a resistance change film provided between the anode electrode and the cathode electrode, and capable of recording information by transitioning between a plurality of states having different resistances in response to at least one of a voltage applied to the resistance change film or a current passed through the resistance change film, the resistance change film including an oxide containing at least one element selected from the group consisting of Hf, Zr, Ni, Ta, W, Co, Al, Fe, Mn, Cr, and Nb; and
an impurity element contained in the resistance change film being at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Sc, Y, La, V, Ta, B, Ga, In, TI, C, Si, Ge, Sn, Pb, N, P, As, Sb, Bi, S, Se, and Te, the impurity element having an atomic radius larger than an atomic radius of the element contained in the oxide, and doping amount of the impurity being 1×10 14 cm −2 or more,
wherein a set voltage of the resistance change film is smaller than a reset voltage of the resistance change film, the set voltage changing a state of the resistance change film from a high resistance state to a low resistance state, and the reset voltage changing a state of the resistance change film from the low resistance state to the high resistance state, and
wherein the anode electrode and the cathode electrode are configured to provide the resistance change film with at least one of the voltage or the current.
9. The device according to claim 8 , wherein the resistance change film includes an impurity doping region being doped with the impurity element, and the impurity doping region is provided near the anode electrode.
10. The device according to claim 8 , wherein the anode electrode and the cathode electrode contain at least one element of W, Ta, Cu, or Si.
11. The device according to claim 8 , wherein the anode electrode and the cathode electrode contain at least one of TiN, TaN, or WC.
12. The device according to claim 8 , further comprising:
a row decoder configured to write data to the nonvolatile memory elements;
a sense amplifier configured to read data from the nonvolatile memory elements; and
a plurality of interconnections electrically connecting between the row decoder and the sense amplifier via the nonvolatile memory elements.
13. The device according to claim 8 , further comprising:
a row decoder configured to write data to the nonvolatile memory elements;
a sense amplifier configured to read data from the nonvolatile memory elements; and
a plurality of interconnections electrically connecting between the row decoder and the sense amplifier via the nonvolatile memory elements,
wherein a concentration of the impurity element in the nonvolatile memory element connected to the interconnection having a relatively high interconnection resistance is relatively higher than a concentration of the impurity element in the nonvolatile memory element connected to the interconnection having a relatively low interconnection resistance.
14. The device according to claim 13 , wherein the nonvolatile memory elements are stacked in multiple layers.
15. The device according to claim 13 , wherein
the nonvolatile memory elements include an anode electrode and a cathode electrode configured to provide the resistance change film with at least one of the voltage or the current, and
a diode is provided between the interconnections and the cathode electrode.
16. The device according to claim 8 , further comprising:
a row decoder configured to write data to the plurality of nonvolatile memory elements;
a sense amplifier configured to read data from the plurality of nonvolatile memory elements; and
a plurality of interconnections electrically connecting the row decoder and the sense amplifier via the nonvolatile memory elements,
a concentration of the impurity element in the nonvolatile memory element connected to the interconnection having a relatively low interconnection resistance is relatively higher than a concentration of the impurity element in the nonvolatile memory element connected to the interconnection having a relatively high interconnection resistance.
17. The device according to claim 16 , wherein the nonvolatile memory elements are stacked in multiple layers.
18. The device according to claim 16 , wherein
the nonvolatile memory elements include an anode electrode and a cathode electrode configured to provide the resistance change film with at least one of the voltage or the current, and
a diode is provided between the interconnections and the cathode electrode.