Semiconductor device

1. A semiconductor device comprising:

a substrate;

a lower electrode structure above the substrate and extending in a direction crossing an upper surface of the substrate;

a dielectric layer on side surfaces and an upper surface of the lower electrode structure; and

an upper electrode structure on the dielectric layer,

wherein the lower electrode structure comprises:

a first lower electrode pattern having a cylindrical shape comprising a side wall and a floor portion;

a barrier layer on an inner surface of the first lower electrode pattern; and

a second lower electrode pattern in a space defined by the barrier layer,

wherein the first lower electrode pattern comprises:

a first portion comprising a first metal element, the first portion including a center portion of the floor portion; and

a second portion comprising an oxide of the first portion.

2. The semiconductor device of claim 1 , wherein the first portion and the second portion are adjacent to each other with an interface therebetween,

wherein the interface is on the side wall of the first lower electrode pattern.

3. The semiconductor device of claim 1 , wherein the first portion and the second portion are adjacent to each other with an interface therebetween,

wherein the interface is on the floor portion of the first lower electrode pattern.

4. The semiconductor device of claim 1 , wherein the first portion comprises titanium nitride (TiN), and

the second portion comprises titanium oxynitride (TiON) and/or titanium oxide (TiO 2 ).

5. The semiconductor device of claim 1 , wherein the first portion comprises titanium nitride (TiN), and

the second portion comprises titanium oxynitride (TiON) and titanium oxide (TiO 2 ).

6. The semiconductor device of claim 1 , wherein a resistance of the second portion is greater than that of the first portion.

7. The semiconductor device of claim 1 , further comprising a transition section between the first portion and the second portion,

wherein a concentration of the oxide of the first portion gradually increases in the transition section.

8. The semiconductor device of claim 7 , wherein, in the transition section, the concentration of the oxide of the first portion gradually increases in a direction from the first portion to the second portion.

9. The semiconductor device of claim 1 , wherein the barrier layer has a multilayer structure in which a metal nitride layer and a silicon nitride layer are alternately stacked at least once.

10. The semiconductor device of claim 1 , wherein the barrier layer has a multilayer structure comprising silicon, the multilayer structure comprising a structure in which a first barrier layer and a second barrier layer are sequentially stacked,

wherein the first barrier layer abuts the first lower electrode pattern, and the second barrier layer abuts the second lower electrode pattern,

wherein a silicon concentration of the second barrier layer is lower than that of the first barrier layer.

11. A semiconductor device comprising:

a substrate;

a lower electrode structure above the substrate and extending in a direction crossing an upper surface of the substrate;

a dielectric layer on side surfaces and an upper surface of the lower electrode structure; and

an upper electrode structure on the dielectric layer,

wherein the lower electrode structure comprises:

a first lower electrode pattern having a cylindrical shape comprising a side wall and a floor portion;

a barrier layer on an inner surface of the first lower electrode pattern; and

a second lower electrode pattern in a space defined by the barrier layer and having a cylindrical shape comprising a side wall and a floor portion,

wherein an outer side wall of the first lower electrode pattern is covered by an interlayer insulation layer, and

wherein the second lower electrode pattern comprises a first portion comprising a first metal element and a second portion comprising an oxide of the first portion.

12. The semiconductor device of claim 11 , wherein the first lower electrode pattern comprises a first portion comprising a first metal element, and

the second lower electrode pattern comprises an oxide of the first portion.

13. The semiconductor device of claim 11 , wherein the dielectric layer and the upper electrode structure are inserted in a space defined by the second lower electrode pattern.

14. The semiconductor device of claim 13 , wherein the dielectric layer covers an inner surface and an upper surface of the second lower electrode pattern.

15. The semiconductor device of claim 14 , wherein the dielectric layer horizontally extends to cover an upper surface of the barrier layer and an upper surface of the first lower electrode pattern.

16. The semiconductor device of claim 15 , wherein the dielectric layer is connected to a dielectric layer of a neighboring semiconductor device at substantially the same level as an upper surface of the first lower electrode pattern.

17. The semiconductor device of claim 15 , wherein the dielectric layer does not extend onto an outer side wall of the first lower electrode pattern.

18. A semiconductor device comprising:

a substrate;

a first interlayer insulation layer on the substrate and exposing an upper surface of a contact plug;

a first lower electrode pattern having a cylindrical shape comprising a floor portion and a side wall, wherein the floor portion is connected to the contact plug, and the side wall extends in a direction crossing the floor portion;

a barrier layer extending along an inner side wall of the first lower electrode pattern;

a second lower electrode pattern in a space defined by the barrier layer;

a dielectric layer contacting upper surfaces of the first lower electrode pattern, the barrier layer, and the second lower electrode pattern; and

an upper electrode structure facing the second lower electrode pattern with the dielectric layer therebetween,

wherein the first lower electrode pattern comprises:

a first portion having a first resistance; and

a second portion having a second resistance 10 times or greater compared to the first resistance,

wherein the first portion directly contacts the contact plug, and

wherein at least a portion of the second portion is located over an outer side wall of the first portion.