Cylindrical capacitor
The present disclosure provides a cylindrical capacitor. The cylindrical capacitor includes a first electrode, a dielectric layer, and a second electrode. The first electrode has a shape of a hollow cylinder and includes oxidized surface portions, first metal-containing layers, and a first hard layer. The oxidized surface portions are at cylindrical surfaces of the hollow cylinder of the first electrode. The first metal-containing layers are between the oxidized surface portions. The first hard layer is disposed between the first metal-containing layers, and a hardness of the first hard layer is larger than hardnesses of the oxidized surface portions and the first metal-containing layers. The dielectric layer is disposed on the first electrode. The second electrode is disposed on the dielectric layer.
1 . A cylindrical capacitor, comprising:
a first electrode having a shape of a hollow cylinder, wherein the first electrode comprises:
oxidized surface portions at cylindrical surfaces of the hollow cylinder of the first electrode;
first metal-containing layers between the oxidized surface portions; and
a first hard layer disposed between the first metal-containing layers, and a hardness of the first hard layer is larger than hardnesses of the oxidized surface portions and the first metal-containing layers;
a dielectric layer disposed on the first electrode; and
a second electrode disposed on the dielectric layer.
2 . The cylindrical capacitor of claim 1 , wherein the first hard layer comprises at least one selected from the group consisting of a silicon layer, a carbon layer, and an aluminum layer.
3 . The cylindrical capacitor of claim 1 , wherein the first metal-containing layers comprise at least one selected from the group consisting of titanium nitride and titanium silicon nitride, and the oxidized surface portions comprise at least one selected from the group consisting of titanium oxynitride, titanium oxide, and titanium silicon oxynitride.
4 . The cylindrical capacitor of claim 1 , wherein the first hard layer is away from the cylindrical surfaces of the hollow cylinder of the first electrode with distances which are from 0.4 to 0.6 times a thickness of the first electrode.
5 . The cylindrical capacitor of claim 4 , wherein the thickness of the first electrode is from 40 Å to 100 Å.
6 . The cylindrical capacitor of claim 1 , wherein a ratio of a thickness of the first hard layer to a total thickness of the oxidized surface portions and the first metal-containing layers is from 0.02 to 0.3.
7 . The cylindrical capacitor of claim 1 , wherein the first hard layer is separated from the oxidized surface portions by the first metal-containing layers.
8 . The cylindrical capacitor of claim 1 , wherein the oxidized surface portions are in direct contact with the dielectric layer, and the first metal-containing layers and the first hard layer are separated from the dielectric layer by the oxidized surface portions.
9 . The cylindrical capacitor of claim 1 , wherein a thickness of each of the oxidized surface portions is from 5 Å to 10 Å.
10 . The cylindrical capacitor of claim 1 , wherein the second electrode comprises second metal-containing layers and a second hard layer between the second metal-containing layers, and a hardness of the second hard layer is larger than hardnesses of the second metal-containing layers.