Memory device and method for manufacturing the same
According to one embodiment, a memory device includes a pillar, a first wiring, a second wiring, an insulating film provided between the first wiring and the second wiring, a first layer provided between the first wiring and the pillar in the second direction and including a first metal oxide containing a first metal and oxygen, a second layer provided between the second wiring and the pillar in the second direction and including the first metal oxide containing the first metal and oxygen, and an intermediate film provided between the pillar and the first layer and between the pillar and the second layer in the second direction and including a second metal oxide containing the first metal and oxygen. Concentration of oxygen contained in the first metal oxide is lower than concentration of oxygen contained in the second metal oxide.
1. A memory device comprising:
a pillar extending in a first direction;
a first wiring apart from the pillar in a second direction crossing the first direction, the first wiring extending in a third direction crossing the first direction and the second direction;
a second wiring apart from the first wiring in the first direction and extending in the third direction;
an insulating film provided between the first wiring and the second wiring;
a first layer provided between the first wiring and the pillar in the second direction and including a first metal oxide containing a first metal and oxygen;
a second layer provided between the second wiring and the pillar in the second direction and including the first metal oxide containing the first metal and oxygen;
an intermediate film provided between the pillar and the first layer in the second direction and between the pillar and the second layer in the second direction, intermediate film including a second metal oxide containing the first metal and oxygen,
a concentration of oxygen contained in the first metal oxide being lower than a concentration of oxygen contained in the second metal oxide; and
a metal film provided at a first position between the first wiring and the insulating film and a second position between the second wiring and the insulating film.
2. The device according to claim 1 , wherein an amount of oxygen deficiency per a unit volume in the first layer is larger than an amount of oxygen deficiency per the unit volume in the intermediate film, and an amount of oxygen deficiency per the unit volume in the second layer is larger than the amount of oxygen deficiency per the unit volume in the intermediate film.
3. The device according to claim 1 , wherein the first metal includes at least one selected from the group consisting of hafnium, titanium, tantalum, zirconium, and nickel.
4. The device according to claim 1 , wherein a first thickness of the intermediate film between the pillar and the first wiring in the second direction on a straight line parallel to the second direction is thinner than a second thickness of the intermediate film between the pillar and the insulating film in the second direction on the straight line.
5. The device according to claim 1 , wherein the metal film includes at least one selected from the group consisting of hafnium, titanium, tantalum, zirconium, and nickel.
6. The device according to claim 1 , further comprising:
a third layer provided between the first wiring and the first layer and between the second wiring and the second layer,
wherein the third layer includes a third metal oxide containing a second metal and oxygen.
7. The device according to claim 6 , wherein the second metal includes at least one selected from the group consisting of hafnium, titanium, tantalum, zirconium, and nickel.
8. The device according to claim 6 , wherein a standard electrode potential of the second metal is lower than a standard electrode potential of the first metal.