Selection element-integrated phase-change memory and method for producing same
Provided are a selection element which does not need an intermediate electrode and thus has improved integration, a phase-change memory device having the selection element, and a phase-change memory implemented so that the phase-change memory device has a highly integrated three-dimensional architecture.
1. A selection element-integrated phase-change element used in a phase-change memory device, the selection element-integrated phase-change element comprising:
a phase-change material layer of P type having a crystal state changing due to heat supplied from a first electrode and a second electrode included in the phase-change memory device; and
a metal oxide layer of N type contacting the phase-change material layer,
wherein the selection element-integrated phase-change element is formed in a PN diode structure to selectively switch, to the phase-change material layer, heat supplied from the first electrode and the second electrode.
2. The selection element-integrated phase-change element of claim 1 , wherein the metal oxide layer is formed of an oxide semiconductor material including at least one cation of Zn, In, or Ga.
3. The selection element-integrated phase-change element of claim 2 , wherein the metal oxide layer is formed of a ZnO x -based material.
4. The selection element-integrated phase-change element of claim 3 , wherein the ZnO x -based material includes at least one of AZO, ZTO, IZO, ITO, IGZO, or Ag—ZnO.
5. The selection element-integrated phase-change element of claim 1 , wherein the phase-change material layer is formed of a compound, in which a transition metal is included in a phase-change material, to have a reverse phase-change characteristic in which the phase-change material layer has high resistance when a crystal state thereof is crystalline and has low resistance when the crystal state thereof is amorphous.
6. The selection element-integrated phase-change element of claim 5 , wherein a composition ratio in which the transition metal is included in the phase-change material is adjusted to maximize a resistance ratio of the phase-change material layer between when the crystal state thereof is crystalline and when the crystal state thereof is amorphous.
7. The selection element-integrated phase-change element of claim 5 , wherein the phase-change material includes at least one of Ge, Sb, or Te, and
the transition metal includes at least one of Cr, Ti, Ni, Zn, Cu, or Mo.
8. A method of producing a selection element-integrated phase-change element used in a phase-change memory device, the method comprising:
forming a phase-change material layer of P type having a crystal state changing due to heat supplied from a first electrode and a second electrode included in the phase-change memory device; and
forming a metal oxide layer of N type so that the metal oxide layer contacts the phase-change material layer,
wherein the selection element-integrated phase-change element is formed in a PN diode structure to selectively switch, to the phase-change material layer, heat supplied from the first electrode and the second electrode.
9. A phase-change memory device comprising:
a first electrode;
a second electrode;
a phase-change material layer between the first electrode and the second electrode; and
a semiconductor material layer arranged between one of the first electrode or the second electrode and the phase-change material layer and operating as a selection element for the phase-change material layer by using Schottky diode characteristics of a contact interface with the one electrode.
10. The phase-change memory device of claim 9 , wherein the one electrode and the semiconductor material layer form a PN diode structure to selectively switch, to the phase-change material layer, heat supplied from the first electrode and the second electrode.
11. The phase-change memory device of claim 10 , wherein the one electrode and the semiconductor material layer have a PN diode structure as the one electrode is formed P type and the semiconductor material layer is formed N type.
12. The phase-change memory device of claim 10 , wherein the semiconductor material layer is formed of an N-type oxide semiconductor material including at least one cation of Zn, In, or Ga.
13. The phase-change memory device of claim 12 , wherein the semiconductor material layer is formed of a ZnO x -based material.
14. The phase-change memory device of claim 13 , wherein the ZnO x -based material includes at least one of AZO, ZTO, IZO, ITO, IGZO, or Ag—ZnO.