Nonvolatile memory device having resistance change layer

1. A nonvolatile memory device comprising:

a substrate;

a resistance change layer disposed on the substrate;

a gate electrode layer disposed on the resistance change layer; and

a first electrode pattern layer and a second electrode pattern layer that are disposed in the substrate and contact different portions of the resistance change layer,

wherein the resistance change layer comprises movable oxygen vacancies or movable metal ions,

wherein the substrate comprises a semiconductor material,

wherein the semiconductor material contacts the resistance change layer,

wherein the resistance change layer has a first resistive material layer disposed on upper surfaces of the first electrode pattern layer, the substrate and the second electrode pattern layer and a second resistive material layer disposed on the first resistive material layer,

wherein a thickness of the first resistive material layer is less than a thickness of the second resistive material layer,

wherein the first resistive material layer has a lower concentration of oxygen vacancies or a lower concentration of movable metal ions compared with the second resistive material layer, and

wherein the nonvolatile memory device further comprises:

first and second trigger filaments formed in the first resistive material layer adjacent to pattern edge portions of the first and second electrode pattern layers, the first and second trigger filaments contacting the first and second electrode pattern layers; and

a connecting filament formed in the second resistive material layer, the connecting filament connecting the first and second trigger filaments,

wherein the first and second trigger filaments are disposed through the first resistive material layer to reach the second resistive material layer to contact the connecting filament,

wherein the first and second trigger filaments are not directly connected with each other, and

wherein diameters of the first and second trigger filaments are greater than a diameter of the connecting filament.

2. The nonvolatile memory device of claim 1 , wherein the gate electrode layer has a plurality of gate pattern layers spaced apart from each other.

3. The nonvolatile memory device of claim 1 ,

wherein the semiconductor material comprises at least one selected from the group consisting of silicon (Si), germanium (Ge), gallium arsenic (GaAs), molybdenum selenide (MoSe 2 ), hafnium selenide (HfSe 2 ), indium selenide (InSe), gallium selenide (GaSe), black phosphorus, and indium-gallium-zinc oxide (IGZO).

4. The nonvolatile memory device of claim 3 , wherein the substrate further comprises a channel formation region disposed between the first electrode pattern layer and the second electrode pattern layer.

5. The nonvolatile memory device of claim 1 , further comprising a gate insulation layer disposed between the resistance change layer and the gate electrode layer.

6. The nonvolatile memory device of claim 1 , wherein a resistivity of the first resistive material layer is higher than a resistivity of the second resistive material layer.

7. The nonvolatile memory device of claim 1 , wherein the resistance change layer has a concentration of oxygen vacancies or a concentration of metal ions which increases from a first interface between the resistance change layer and the substrate to a second interface between the resistance change layer and the gate electrode layer.