According to one embodiment, a semiconductor memory device includes first to nth string units (n being a natural number of 3 or more), a plurality of layers of word lines, and (n−1) layers of select gate layers. The first to nth string units each includes a memory string. The memory string includes a plurality of memory cells and a plurality of select transistors connected in series in a first direction. The (n−1) layers of select gate layers include first to (2×(n−1))th select gates electrically isolated from each other. The first string unit is selected by the first to (n−1)th select gates. The kth string unit (k being not less than 1 and not more than n) is selected by the kth to (n+k−2)th select gates. The nth string unit is selected by the nth to (2×(n−1))th select gates.

Some embodiments include a conductive structure of an integrated circuit. The conductive structure includes an upper primary portion, with the upper primary portion having a first conductive constituent configured as a container. The container has a bottom, and a pair of sidewalls extending upwardly from the bottom. An interior region of the container is over the bottom and between the sidewalls. The upper primary portion includes a second conductive constituent configured as a mass filling the interior region of the container. The second conductive constituent is a different composition than the first conductive constituent. One or more conductive projections join to the upper primary portion and extend downwardly from the upper primary portion. Some embodiments include assemblies comprising memory cells over conductive structures. Some embodiments include methods of forming conductive structures.

A vertically stacked set of an n-type vertical transport field effect transistor (n-type VT FET) and a p-type vertical transport field effect transistor (p-type VT FET) is provided. The vertically stacked set of the n-type VT FET and the p-type VT FET includes a first bottom source/drain layer on a substrate, that has a first conductivity type, a lower channel pillar on the first bottom source/drain layer, and a first top source/drain on the lower channel pillar, that has the first conductivity type. The vertically stacked set of the n-type VT FET and the p-type VT FET further includes a second bottom source/drain on the first top source/drain, that has a second conductivity type different from the first conductivity type, an upper channel pillar on the second bottom source/drain, and a second top source/drain on the upper channel pillar, that has the second conductivity type.

A vertically stacked set of an n-type vertical transport field effect transistor (n-type VT FET) and a p-type vertical transport field effect transistor (p-type VT FET) is provided. The vertically stacked set of the n-type VT FET and the p-type VT FET includes a first bottom source/drain layer on a substrate, that has a first conductivity type, a lower channel pillar on the first bottom source/drain layer, and a first top source/drain on the lower channel pillar, that has the first conductivity type. The vertically stacked set of the n-type VT FET and the p-type VT FET further includes a second bottom source/drain on the first top source/drain, that has a second conductivity type different from the first conductivity type, an upper channel pillar on the second bottom source/drain, and a second top source/drain on the upper channel pillar, that has the second conductivity type.

Methods of forming 3D NAND devices are discussed. Some embodiments form 3D NAND devices with a control gate and a floating gate disposed between a first insulating layer and a second insulating layer. A conformal blocking liner surrounds the floating gate and electrically isolates the control gate from the floating gate. Some embodiments form 3D NAND devices with decreased vertical and/or later pitch between cells.

A field effect transistor construction includes a semiconductive channel core. A source/drain region is at opposite ends of the channel core. A gate is proximate a periphery of the channel core. A gate insulator is between the gate and the channel core. The gate insulator has local regions radially there-through that have different capacitance at different circumferential locations relative to the channel core periphery. Additional constructions, and methods, are disclosed.

In one embodiment, a semiconductor device includes a substrate, insulating films and first films alternately stacked on the substrate, at least one of the first films including an electrode layer and a charge storage layer provided on a face of the electrode layer via a first insulator, and a semiconductor layer provided on a face of the charge storage layer via a second insulator. The device further includes at least one of a first portion including nitrogen and provided between the first insulator and the charge storage layer with an air gap provided in the first insulator, a second portion including nitrogen, provided between the charge storage layer and the second insulator, and including a portion protruding toward the charge storage layer, and a third portion including nitrogen and provided between the second insulator and the semiconductor layer with an air gap provided in the first insulator.

Methods of forming 3D NAND devices are discussed. Some embodiments form 3D NAND devices with a control gate and a floating gate disposed between a first insulating layer and a second insulating layer. A conformal blocking liner surrounds the floating gate and electrically isolates the control gate from the floating gate. Some embodiments form 3D NAND devices with decreased vertical and/or later pitch between cells.

An object is to provide a semiconductor device with large memory capacity. The semiconductor device includes first to seventh insulators, a first conductor, and a first semiconductor. The first conductor is positioned on a first top surface of the first insulator and a first bottom surface of the second insulator. The third insulator is positioned in a region including a side surface and a second top surface of the first insulator, a side surface of the first conductor, and a second bottom surface and a side surface of the second insulator. The fourth insulator, the fifth insulator, and the first semiconductor are sequentially stacked on the third insulator. The sixth insulator is in contact with the fifth insulator in a region overlapping the first conductor. The seventh insulator is positioned in a region including the first semiconductor and the sixth insulator.

A method of forming a semiconductor device includes forming, on a lower structure, a mold structure having interlayer insulating layers and gate layers alternately and repeatedly stacked. Each of the gate layers is formed of a first layer, a second layer, and a third layer sequentially stacked. The first and third layers include a first material, and the second layer includes a second material having an etch selectivity different from an etch selectivity of the first material. A hole formed to pass through the mold structure exposes side surfaces of the interlayer insulating layers and side surfaces of the gate layers. Gate layers exposed by the hole are etched, with an etching speed of the second material differing from an etching speed of the first material, to create recessed regions.