Memory device and fabrication method thereof
A memory device includes a first electrode, a first support layer, a dielectric layer and a second electrode. The first electrode is disposed on a substrate and extending upwards. The first support layer laterally supports an upper portion of a sidewall of the first electrode, where the first support layer has a slim portion. The dielectric layer is disposed on the first electrode and the first support layer. The second electrode is disposed on the dielectric layer. In addition, a method of fabricating the memory device is provided.
1. A memory device, comprising:
a first electrode, disposed on a substrate and extending upwards;
a first support layer, laterally supporting an upper portion of a sidewall of the first electrode, wherein the first support layer has a slim portion and a recessed sidewall located on the slim portion;
a dielectric layer, disposed on the first electrode and the first support layer, and in direct contact with the recessed sidewall; and
a second electrode, disposed on the dielectric layer.
2. The memory device of claim 1 , wherein a top width of the first support layer is smaller than a bottom width of the first support layer in a direction perpendicular to the sidewall of the first electrode.
3. The memory device of claim 1 , wherein a topmost surface of the first electrode is lower than a topmost surface of the first support layer.
4. The memory device of claim 1 , wherein the first support layer comprises a first insulating layer and a second insulating layer, and the first insulating layer is disposed on the second insulating layer.
5. The memory device of claim 4 , wherein a topmost surface of the first electrode is higher than a topmost surface of the second insulating layer.
6. The memory device of claim 4 , wherein the slim portion of the first support layer is located on the first insulating layer, and a top width of the first insulating layer is smaller than a bottom width of the first insulating layer in a direction perpendicular to the sidewall of the first electrode.
7. The memory device of claim 4 , wherein the slim portion of the first support layer is located on the second insulating layer, and a top width of the second insulating layer is smaller than a bottom width of the second insulating layer in a direction perpendicular to the sidewall of the first electrode.
8. The memory device of claim 4 , wherein a width of the first insulating layer is equal to a top width of the second insulating layer in a direction perpendicular to the sidewall of the first electrode.
9. The memory device of claim 4 , wherein widths of the first insulating layer are gradually decreased in a direction from the bottom to the top of the first insulating layer.
10. The memory device of claim 4 , wherein the first insulating layer is doped with carbon, and the second insulating layer is not doped with carbon.
11. The memory device of claim 4 , wherein the material of the first insulating layer comprises a carbon-doped silicon nitride, a carbon-doped silicon oxide or a carbon-doped silicon oxynitride.
12. The memory device of claim 1 , wherein there is a gap between the dielectric layer, and the second electrode is disposed in the gap or fills up the gap.
13. The memory device of claim 1 , wherein the first support layer has an L-shaped sidewall or an inclined sidewall.
14. The memory device of claim 1 , wherein there is a gap between the first electrode and the first support layer, and the dielectric layer is disposed in the gap or fills up the gap.
15. The memory device of claim 1 , further comprising a second support layer laterally supporting a lower portion of the sidewall of the first electrode and spaced from the first support layer, wherein the dielectric layer is disposed on the second support layer.
16. A method of fabricating a memory device, comprising:
forming a first electrode on a substrate and extending upwards;
forming a first support layer laterally supporting an upper portion of a sidewall of the first electrode, wherein the first support layer has a slim portion and a recessed sidewall located on the slim portion;
forming a dielectric layer on the first electrode and the first support layer, and in direct contact with the recessed sidewall; and
forming a second electrode on the dielectric layer.
17. The method of fabricating the memory device of claim 16 , wherein forming the first electrode and forming the first support layer comprise:
forming a sacrificial material layer and a first support material layer on the substrate in sequence, wherein the first support material layer comprises a first insulating material layer that is doped with carbon and a second insulating material layer that is not doped with carbon, and the first insulating material layer is formed on the second insulating material layer;
etching the first support material layer and the sacrificial material layer to form a plurality of first openings to expose the substrate;
forming the first electrode in the plurality of first openings;
etching the first support material layer to form a plurality of second openings to expose the sacrificial material layer; and
removing the sacrificial material layer through the plurality of second openings and etching a portion of the first support material layer in an etching process to form the first support layer, wherein a top width of the first support layer is smaller than a bottom width of the first support layer in a direction perpendicular to the sidewall of the first electrode.
18. The method of fabricating the memory device of claim 17 , wherein etching the portion of the first support material layer comprises:
etching a portion of the first insulating material layer to form the slim portion of the first support layer, wherein a top width of the remaining first insulating material layer is smaller than a bottom width of the remaining first insulating material layer in a direction perpendicular to the sidewall of the first electrode.
19. The method of fabricating the memory device of claim 17 , wherein etching the portion of the first support material layer comprises:
etching a portion of the first insulating material layer and a portion of the second insulating material layer to form the slim portion of the first support layer, wherein a top width of the remaining second insulating material layer is smaller than a bottom width of the remaining second insulating material layer, and a width of the remaining first insulating material layer is equal to the top width of the remaining second insulating material layer in a direction perpendicular to the sidewall of the first electrode.
20. The method of fabricating the memory device of claim 17 , wherein the sacrificial material layer comprises a first sacrificial material layer and a second sacrificial material layer, and the first sacrificial material layer is formed above the second sacrificial material layer, and further comprising:
forming a second support layer between the first sacrificial material layer and the second sacrificial material layer, wherein after the sacrificial material layer is removed, the second support layer is spaced from the first support layer and laterally supports a lower portion of the sidewall of the first electrode, and the dielectric layer is formed on the second support layer.