Memory device and method for driving same
A memory device includes a first interconnect extending in a first direction, a second interconnect extending in a second direction crossing the first direction, a third interconnect extending in a third direction crossing a plane including the first direction and the second direction, a fourth interconnect extending in the third direction, a semiconductor member, a first resistance change film, and a second resistance change film. The semiconductor member is connected between a first end of the second interconnect and the first interconnect. The first resistance change film is connected between a side surface of the second interconnect and the third interconnect. The second resistance change film is connected between a second end of the second interconnect and the fourth interconnect.
1. A memory device comprising:
a first interconnect extending in a first direction;
a second interconnect extending in a second direction crossing the first direction;
a third interconnect extending in a third direction crossing a plane including the first direction and the second direction;
a fourth interconnect extending in the third direction;
a semiconductor member connected between a first end of the second interconnect and the first interconnect;
a first resistance change film connected between a side surface of the second interconnect and the third interconnect; and
a second resistance change film connected between a second end of the second interconnect and the fourth interconnect.
2. The device according to claim 1 , wherein
the first end and the second end are both ends in the second direction of the second interconnect, and
the side surface is a surface facing the first direction of the second interconnect.
3. The device according to claim 1 , further comprising:
an electrode placed on the first direction side of the semiconductor member and extending in the third direction.
4. The device according to claim 1 , wherein
the second resistance change film includes:
a nonlinear resistance layer having a resistance value depending on voltage; and
a resistance change layer, and
the nonlinear resistance layer and the resistance change layer are connected in series between the second interconnect and the fourth interconnect.
5. The device according to claim 4 , wherein the nonlinear resistance layer contains silicon, nitrogen, and at least one of tantalum and titanium.
6. The device according to claim 1 , wherein the second resistance change film can assume three or more states different in resistance value.
7. The device according to claim 6 , further comprising:
a control circuit,
wherein the control circuit brings the semiconductor member into conduction and applies a first voltage, a second voltage of opposite polarity to the first voltage, or a third voltage having the same polarity as the second voltage and having a larger absolute value than the second voltage between the first interconnect and the fourth interconnect.
8. The device according to claim 7 , wherein
the control circuit changes a resistance value of the first resistance change film into a value corresponding to the second voltage by applying a voltage between the fourth interconnect and the third interconnect, after applying the second voltage between the first interconnect and the fourth interconnect, and
the control circuit changes a resistance value of the first resistance change film into a value corresponding to the third voltage by applying a voltage between the fourth interconnect and the third interconnect, after applying the third voltage between the first interconnect and the fourth interconnect.
9. The device according to claim 7 , wherein the control circuit brings the semiconductor member into conduction and applies a voltage between the first interconnect and the third interconnect after applying the first voltage between the first interconnect and the fourth interconnect while data is read.
10. The device according to claim 7 , wherein the control circuit turns the first resistance change film to a state of highest resistance value by bringing the semiconductor member into conduction and applying a voltage between the first interconnect and the third interconnect after applying the first voltage between the first interconnect and the fourth interconnect.
11. The device according to claim 7 , wherein
the control circuit changes a resistance value of the first resistance change film into a value corresponding to the second voltage by applying a voltage between the fourth interconnect and the third interconnect, after bringing the semiconductor member into conduction and applying the second voltage between the first interconnect and the fourth interconnect, or the control circuit changes a resistance value of the first resistance change film into a value corresponding to the third voltage by applying a voltage between the fourth interconnect and the third interconnect, after bringing the semiconductor member into conduction and applying the third voltage between the first interconnect and the fourth interconnect, then
the control circuit brings the semiconductor member into conduction and applies the first voltage between the first interconnect and the fourth interconnect.