US Patent 11864389 Semiconductor memory device

A semiconductor memory device includes a substrate; a plurality of first conductive layers and first insulating layers stacked in alternation; a first semiconductor layer opposed to first conductive layers and first insulating layers; a second semiconductor layer; a second insulating layer that covers outer peripheral surface of the first semiconductor layer; and a third insulating layer disposed at a position different from first conductive layers, first insulating layers, and the second insulating layer, the third insulating layer having one end in contact with the second semiconductor, the third insulating layer having another end farther from the second semiconductor layer than the second insulating layer. A metal oxide film is disposed on a surface on the third insulating layer side of the second insulating layer. A metal oxide film is absent on a surface on the third insulating layer side of the plurality of first insulating layers.