Three-dimensional semiconductor memory device and method of fabricating the same
A semiconductor memory device includes a cell string and a first conductive pillar and a second conductive pillar connected to the cell string. The cell string includes plural memory cells, which are stacked on a substrate to be spaced apart from each other. The first conductive pillar is spaced apart from the second conductive pillar in a first direction. Each of the memory cells includes a channel layer that extends from the first conductive pillar to the second conductive pillar in the first direction, a ferroelectric layer on the channel layer, and an electrode on the ferroelectric layer. The channel layer comprises single crystalline silicon.
1 . A semiconductor memory device comprising:
a cell string including a plurality of memory cells, the plurality of memory cells being stacked on a substrate to be spaced apart from each other; and
a first conductive pillar and a second conductive pillar connected to the cell string,
wherein the first conductive pillar is spaced apart from the second conductive pillar in a first direction,
wherein each of the plurality of memory cells comprises:
a channel layer that extends from the first conductive pillar to the second conductive pillar in the first direction;
a ferroelectric layer on the channel layer; and
an electrode on the ferroelectric layer,
wherein the channel layer comprises single crystalline silicon, and
wherein the channel layers of the plurality of memory cells are spaced apart from each other in a vertical direction that is orthogonal to a top surface of the substrate.
2 . The semiconductor memory device of claim 1 , wherein the ferroelectric layer covers a top surface, a bottom surface, and a first side surface of the electrode and exposes a second side surface, which is opposite to the first side surface of the electrode.
3 . The semiconductor memory device of claim 2 , wherein the ferroelectric layer covers a side surface of the channel layer, and
an opposite side surface of the channel layer is connected to the first conductive pillar and to the second conductive pillar.
4 . The semiconductor memory device of claim 1 , wherein the ferroelectric layer comprises a hafnium-based oxide containing at least one impurity selected from the group consisting of Zr, Si, Al, Y, Gd, La, Sc, and Sr.
5 . The semiconductor memory device of claim 1 , wherein the ferroelectric layer comprises a first layer and a second layer, which are sequentially stacked,
one of the first layer and the second layer comprises a ferroelectric material, and
a remaining one of the first layer and the second layer comprises a paraelectric material.
6 . The semiconductor memory device of claim 1 , wherein each of the plurality of memory cells further comprises:
a first metal pattern between the channel layer and the ferroelectric layer; and
a second metal pattern between the ferroelectric layer and the electrode.
7 . The semiconductor memory device of claim 1 , further comprising insulating patterns, which are respectively interposed between the first conductive pillar and the second conductive pillar and the substrate.
8 . The semiconductor memory device of claim 1 , wherein the electrode has a line shape extending along the first direction.
9 . The semiconductor memory device of claim 1 , further comprising:
a peripheral circuit layer on the substrate, the peripheral circuit layer comprising peripheral transistors; and
an interlayer insulating layer on the substrate, the interlayer insulating layer covering the peripheral transistors.
10 . A semiconductor memory device comprising:
a stack on a substrate;
a conductive pillar, which is provided adjacent to the stack and extends in a vertical direction that is orthogonal to a top surface of the substrate; and
an insulating pattern between the conductive pillar and the substrate,
wherein the stack comprises:
electrodes stacked on the substrate;
a ferroelectric layer covering the electrodes; and
channel layers, which are respectively interposed between the electrodes and the conductive pillar,
wherein the channel layers are spaced apart from each other in the vertical direction, and
wherein the insulating pattern electrically disconnects the conductive pillar from the substrate.
11 . The semiconductor memory device of claim 10 , wherein the insulating pattern comprises an oxidized semiconductor layer grown from the substrate.
12 . The semiconductor memory device of claim 10 , wherein the channel layers are single crystalline silicon patterns, which are split to be spaced apart from each other.
13 . The semiconductor memory device of claim 10 , wherein the ferroelectric layer covers a top surface, a bottom surface, and a first side surface of each of the electrodes and exposes a second side surface of each of the electrodes, and
the second side surface is opposite to the first side surface.
14 . The semiconductor memory device of claim 13 , wherein the ferroelectric layer covers a side surface of each of the channel layers, and
an opposite side surface of each of the channel layers is connected to the conductive pillar.
15 . A semiconductor memory device comprising:
a first cell string and a second cell string on a substrate; and
a first conductive pillar and a second conductive pillar between the first cell string and the second cell string,
wherein the first conductive pillar is spaced apart from the second conductive pillar in a first direction,
wherein the first cell string is spaced apart from the second cell string in a second direction,
wherein each of the first cell string and the second cell string comprises:
electrodes stacked on the substrate;
channel layers, which are respectively disposed adjacent to the electrodes and are spaced apart from each other in a third direction that is orthogonal to the first direction and the second direction, each of the channel layers connecting the first conductive pillar to the second conductive pillar; and
a ferroelectric layer interposed between the electrodes and the channel layers, and
wherein the ferroelectric layer covers a top surface, a bottom surface, and a first side surface of each of the electrodes.
16 . The semiconductor memory device of claim 15 , wherein the ferroelectric layer exposes a second side surface of each of the electrodes, and
the second side surface is opposite to the first side surface in the second direction.
17 . The semiconductor memory device of claim 15 , wherein the channel layers are single crystalline silicon patterns, which are split to be spaced apart from each other.
18 . The semiconductor memory device of claim 15 , wherein each of the channel layers has a bar shape extending in the first direction from the first conductive pillar to the second conductive pillar.
19 . The semiconductor memory device of claim 15 , further comprising insulating patterns, which are respectively interposed between the first conductive pillar to the second conductive pillar and the substrate.