Semiconductor memory device and method for manufacturing same
A semiconductor memory device having one embodiment which includes a substrate; a stacked body provided on the substrate and including a plurality of electrode layers separately stacked; a first upper layer gate provided on the stacked body; an interlayer insulating layer provided on the first upper layer gate; an insulating part continuously provided from the first upper layer gate to the substrate and extending in a first direction parallel to a major surface of the substrate; a second upper layer gate; a semiconductor part; a charge storage film; and a semiconductor layer provided from an upper end of the semiconductor part to a portion of the semiconductor part reaching the second upper layer gate. The second upper layer gate is provided on the interlayer insulating layer and the insulating part, and extends on a first surface parallel to the major surface.
1. A semiconductor memory device comprising:
a substrate;
a stacked body provided on the substrate and including a plurality of electrode layers separately stacked;
a first upper layer gate provided on the stacked body;
an interlayer insulating layer provided on the first upper layer gate;
an insulating part continuously provided from the first upper layer gate to the substrate and extending in a first direction parallel to a major surface of the substrate;
a second upper layer gate provided on the interlayer insulating layer and the insulating part, and extending on a first surface parallel to the major surface;
a semiconductor part extending from the second upper layer gate to the substrate, the semiconductor part being insulated from the second upper layer gate;
a charge storage portion provided between the semiconductor part and one of the plurality of electrode layers; and
a semiconductor layer provided from an upper end of the semiconductor part to a portion of the semiconductor part reaching the second upper layer gate, the semiconductor layer being disposed inside the semiconductor part, a lower end of the semiconductor layer being located higher than an interface between the second upper layer gate and the interlayer insulating layer.
2. The semiconductor memory device according to claim 1 , wherein a maximum diameter of a section of the upper end of the semiconductor part parallel to the major surface of the substrate is smaller than a maximum diameter of a section of a portion of the semiconductor part adjacent to the interlayer insulating layer and parallel to the major surface.
3. The semiconductor memory device according to claim 1 , wherein
the insulating part includes a source layer electrically connected to the substrate; and
the semiconductor memory device further comprises a plurality of contact parts extending from the second upper layer gate to the source layer, and separated and provided in the first direction.
4. The semiconductor memory device according to claim 3 , wherein as viewed in a stacking direction of the stacked body, a shape of each of the plurality of contact parts is circular.
5. The semiconductor memory device according to claim 3 , wherein as viewed in a stacking direction of the stacked body, a shape of each of the plurality of contact parts is square.
6. The semiconductor memory device according to claim 1 , wherein the semiconductor layer is separated from the second upper layer gate.
7. The semiconductor memory device according to claim 1 , further comprising an insulating film provided inside the semiconductor part, wherein
an upper surface of the insulating film contacts the semiconductor layer.
8. The semiconductor memory device according to claim 1 , wherein a thickness of the first upper layer gate is thicker than a thickness of the plurality of electrode layers.
9. The semiconductor memory device according to claim 1 , wherein an impurity concentration of the semiconductor layer is higher than an impurity concentration of the semiconductor part.