Resistance variable nonvolatile memory device
Each of memory cells (MC) includes one transistor and one resistance variable element. The transistor includes a first main terminal, a second main terminal and a control terminal. The resistance variable element includes a first electrode, a second electrode and a resistance variable layer provided between the first electrode and the second electrode. A first main terminal of one of two adjacent memory cells is connected to a second main terminal of the other memory cell, to form a series path (SP) sequentially connecting main terminals of the plurality of memory cells in series. Each of the memory cells is configured such that the control terminal is a part of a first wire (WL) associated with the memory cell or is connected to the first wire associated with the memory cell, the second electrode is a part of a second wire (SL) associated with the memory cell or is connected to the second wire associated with the memory cell; and the first electrode is a part of a series path (SP) associated with the memory cell or is connected to the series path associated with the memory cell.
1. A nonvolatile memory device comprising:
a plurality of first wires extending in parallel with each other in a first direction within a first plane;
a plurality of second wires extending in parallel with each other in a second direction within a second plane parallel to the first plane such that the plurality of second wires three-dimensionally cross the plurality of first wires, respectively; and
memory cells provided to respectively correspond to three-dimensional cross-points of the first wires and the second wires;
each of the memory cells including one resistance variable element and only one transistor;
the transistor including a first main terminal, a second main terminal and a control terminal;
the resistance variable element including a first electrode, a second electrode and a resistance variable layer provided between the first electrode and the second electrode;
the memory cells including a plurality of memory cells which are arranged along the first direction and configured such that a first main terminal of one of two adjacent memory cells is connected to a second main terminal of the other memory cell, to form a series path extending in the first direction and sequentially connecting main terminals of the plurality of memory cells in series; and
each of the memory cells being configured such that:
the control terminal is connected to a first wire associated with the memory cell;
the second electrode is a part of a second wire associated with the memory cell or is connected to the second wire associated with the memory cell; and
the first electrode is a part of a series path associated with the memory cell or is connected to the series path associated with the memory cell.
2. The nonvolatile memory device according to claim 1 , further comprising:
a plurality of third wires extending in parallel with each other in the first direction,
wherein the plurality of memory cells arranged along the first direction constitute a plurality of memory blocks each of which includes a predetermined number of memory cells arranged successively, and
the series path is connected to the third wire for each of the memory blocks.
3. The nonvolatile memory device according to claim 2 , wherein both ends of the series path are connected to the third wire for each of the memory blocks.
4. The nonvolatile memory device according to claim 2 , further comprising:
an electric power supply circuit for applying voltages to the resistance variable element included in each of the memory cells,
wherein the electric power supply circuit is configured to change output voltages, according to the number of transistors included in a portion of a series path associated with a selected memory cell, from a connecting point of the associated series path and the associated third wire to the first electrode of the selected memory cell.
5. The nonvolatile memory device according to claim 2 ,
wherein the resistance variable element is changed from a high-resistance state to a low-resistance state by application of a first voltage of a first polarity, and the resistance variable element is changed from the low-resistance state to the high-resistance state by application of a second voltage of a second polarity, which is opposite to the first polarity.
6. The nonvolatile memory device according to claim 1 ,
wherein each of the first main terminal and the second main terminal includes a silicide layer; and the silicide layer constitutes the first electrode.
7. The nonvolatile memory device according to claim 6 ,
wherein the silicide layer comprises platinum silicide.
8. The nonvolatile memory device according to claim 1 ,
wherein the resistance variable element is changed from a high-resistance state to a low-resistance state by application of a first voltage of a first polarity, and the resistance variable element is changed from the low-resistance state to the high-resistance state by application of a second voltage of a second polarity, which is opposite to the first polarity.
9. The nonvolatile memory device according to claim 1 ,
wherein the resistance variable element is located below the first wires.