Memory device having a channel provided on a memory unit
A memory device is provided. The memory device includes: a substrate; a memory unit provided on the substrate; a channel provided on the memory unit; a word line surrounded by the channel and extending in a first horizontal direction; a gate insulating layer interposed between the channel and the word line; and a bit line contacting an upper end of the channel and extending in a second horizontal direction that crosses the first horizontal direction.
1. A memory device comprising:
a substrate;
a memory unit provided on the substrate;
a channel provided on the memory unit;
a word line surrounded by the channel and extending in a first horizontal direction;
a gate insulating layer interposed between the channel and the word line; and
a bit line contacting an upper end of the channel and extending in a second horizontal direction that crosses the first horizontal direction.
2. The memory device of claim 1 , wherein the channel comprises an oxide semiconductor.
3. The memory device of claim 2 , wherein the channel comprises indium-gallium-zinc-oxide (IGZO).
4. The memory device of claim 1 , further comprising a memory unit contact that electrically connects the memory unit to the channel.
5. The memory device of claim 1 , wherein the channel comprises:
a first portion provided on a first side of the word line;
a second portion provided on a second side of the word line;
a third portion provided on a lower surface of the word line; and
a fourth portion on an upper surface of the word line.
6. The memory device of claim 1 , wherein the memory unit comprises:
a lower electrode;
an upper electrode; and
a dielectric layer interposed between the lower electrode and the upper electrode.
7. The memory device of claim 6 , wherein the upper electrode has a column shape.
8. A memory device comprising:
a substrate;
a lower electrode provided on the substrate;
an upper electrode provided on the lower electrode;
a dielectric layer provided between the lower electrode and the upper electrode;
a memory unit contact provided on the upper electrode;
a channel comprising a first portion and a second portion, each of the first portion and the second portion extending from the memory unit contact in a vertical direction perpendicular to a first horizontal direction;
a word line extending in the first horizontal direction and passing between the first portion and the second portion of the channel;
a gate insulating layer interposed between the channel and the word line; and
a bit line contacting upper ends of the first portion and the second portion of the channel and extending in a second horizontal direction perpendicular to the vertical direction.
9. The memory device of claim 8 , wherein the channel further comprises:
a third portion interposed between the memory unit contact and the word line; and
a fourth portion between the bit line and the word line.
10. The memory device of claim 9 , wherein the word line comprises:
a line portion extending in the first horizontal direction; and
a contact portion protruding from the line portion toward the third portion of the channel along the vertical direction.
11. A memory device comprising:
a substrate;
a lower electrode provided on the substrate;
a dielectric layer provided on the lower electrode;
a plurality of upper electrodes provided on the dielectric layer;
a plurality of channels respectively provided on the plurality of upper electrodes and extending in a vertical direction;
a plurality of word lines respectively provided on sides of the plurality of channels and extending in a first horizontal direction perpendicular to the vertical direction;
a plurality of gate insulating layers respectively interposed between the plurality of channels and the plurality of word lines; and
a bit line contacting upper ends of the plurality of channels and extending in a second horizontal direction that crosses the first horizontal direction and is perpendicular to the vertical direction.
12. The memory device of claim 11 , wherein the dielectric layer is provided on a side surface and a lower surface of each of the plurality of upper electrodes.
13. The memory device of claim 11 , further comprising an interlayer insulating layer located on the substrate and having a plurality of holes,
wherein the lower electrode is provided on an upper surface of the interlayer insulating layer, and on a side and a bottom of each of the plurality of holes of the interlayer insulating layer, and
the plurality of upper electrodes are respectively provided in the plurality of holes of the interlayer insulating layer.
14. The memory device of claim 13 , further comprising a ground plate interposed between the substrate and the interlayer insulating layer.
15. The memory device of claim 11 , wherein each of the plurality of channels comprises:
a first portion provided on a first side of each of the plurality of word lines; and
a second portion provided on a second side of each of the plurality of word lines, wherein the second side is opposite the first side.
16. The memory device of claim 11 , wherein each of the plurality of word lines comprises:
a first portion provided on a first side of each of the plurality of channels; and
a second portion provided on a second side of each of the plurality of channels, wherein the second side is opposite the first side.
17. The memory device of claim 11 , wherein a dimension of each of the plurality of gate insulating layers in the vertical direction corresponds to a dimension of each of the plurality of word lines in the vertical direction.
18. The memory device of claim 11 , further comprising a capping layer provided on a side of each of the plurality of word lines,
wherein a dimension of the capping layer in the vertical direction corresponds to a dimension of each of the plurality of word lines in the vertical direction.
19. The memory device of claim 11 , wherein the bit line comprises:
a line portion extending in the second horizontal direction; and
a plurality of contact portions respectively protruding from the line portion along the vertical direction and respectively contacting the upper ends of the plurality of channels, and
wherein a dimension of each of the plurality of contact portions in the second horizontal direction corresponds to a dimension of each of the plurality of channels in the second horizontal direction.
20. The memory device of claim 11 , wherein each of the plurality of word lines and each of the plurality of upper electrodes comprise a same material.