Semiconductor memory device
A semiconductor memory device comprising a stacked unit, a semiconductor pillar, a charge storage layer, and a non-insulating film. The stacked unit includes first conductive layers and first insulating layers which are stacked alternately. The semiconductor pillar passes through the stacked body and the semiconductor pillar has a tubular structure. The charge storage layer is provided between the semiconductor pillar and each of the first conductive layers. The non-insulating film is provided inside the tubular structure and has a non-insulating member. The first effective impurity concentration of the non-insulating film is lower than a second effective impurity concentration of the semiconductor pillar.
1. A semiconductor memory device comprising:
a stacked body comprising one or more first conductive layer(s) and one or more first insulating layer(s), which are alternately stacked;
a tubular semiconductor pillar, which comprises a polysilicon to which an impurity is doped, that passes through the layers of the stacked body, wherein the inside of the tubular semiconductor pillar contains a non-insulating member having an effective impurity concentration; and
a charge storage layer provided between the first conductive layer(s) and the tubular semiconductor pillar;
wherein a first effective impurity concentration of the non-insulating member is lower than a second effective impurity concentration of the tubular semiconductor pillar.
2. The device according to claim 1 , wherein the non-insulating member comprises silicon.
3. The device according to claim 1 , further comprising a conductive layer embedded within the tubular semiconductor pillar above the non-insulating member.
4. The device according to claim 1 , further comprising a a first insulating film which is provided between the semiconductor pillar and the non-insulating member.
5. The device according to claim 4 , wherein a film thickness of the first insulating film is not more than 2.5 nm.
6. The device according to claim 1 , wherein an air gap is provided inside the non-insulating member.
7. The device according to claim 1 , further comprising:
a second conductive layer provided on the stacked body that can serve as a selector gate;
a second insulating layer provided on the second conductive layer; and
a second insulating film;
wherein the semiconductor pillar passes through the second conductive layer and the second insulating layer, and the second insulating film is provided between the semiconductor pillar and the second conductive layer.
8. The device according to claim 7 , wherein an air gap is provided inside the non-insulating member, and the air gap is located at a height of the second conductive layer.
9. The device according to claim 7 , wherein a step is located between the second conductive layer and the second insulating layer.
10. The device according to claim 4 , wherein the first insulating film comprises a silicon oxide.