Variable resistance element, semiconductor device including variable resistance element, and methods for manufacturing variable resistance element and semiconductor device
A variable resistance element includes a first electrode, a second electrode and an ion conduction layer interposed between the first and second electrodes. The ion conduction layer contains an organic oxide containing at least oxygen and carbon. The carbon concentration distribution in the ion conduction layer is such that the carbon concentration in an area closer to the first electrode is greater than that in an area closer to the second electrode.
1. A variable resistance element, comprising:
first and second electrodes; and
an ion conduction layer interposed between the first and second electrodes; wherein,
the ion conduction layer contains an organic oxide containing at least oxygen and carbon;
a carbon concentration distribution in the ion conduction layer being such that the carbon concentration in an area of the ion conduction layer closer to the first electrode is greater than that in an area thereof closer to the second electrode.
2. The variable resistance element according to claim 1 , wherein,
the carbon concentration distribution in the ion conduction layer decreases continuously or stepwise from the area on the first electrode side towards the area on the second electrode side.
3. The variable resistance element according to claim 1 , wherein,
the ion conduction layer is a film containing at least silicon as element in addition to oxygen and carbon.
4. The variable resistance element according to claim 3 , wherein,
the ion conduction layer is a film containing an organic matter including a six-membered or eight-membered siloxane structure as a main skeleton.
5. The variable resistance element according to claim 4 , wherein,
the organic matter further includes at least an unsaturated hydrocarbon group.
6. The variable resistance element according to claim 1 , wherein
the ion conduction layer is a porous film.
7. The variable resistance element according to claim 1 , wherein
the ion conduction layer has a dielectric constant not less than 2.5 and not greater than 3.5.
8. The variable resistance element according to claim 1 , wherein
the material of the first electrode comprises copper.
9. The variable resistance element according to claim 8 , further comprising:
a titanium oxide layer interposed between the ion conduction layer and copper of the first electrode, the ion conduction layer containing titanium.
10. A method for manufacturing a variable resistance element having a layered structure of a first electrode, an ion conduction layer containing an organic oxide, and a second electrode, layered in this order, comprising:
a plasma CVD process for forming the ion conduction layer containing the organic oxide, the plasma CVD process employing a vapor of an organic silica compound and an inert gas for dilution, the organic silica compound including a skeleton composed by at least silicon, carbon and oxygen; wherein
the plasma CVD process includes varying, either continuously or stepwise, the high frequency power for plasma initiation or the partial pressure of the vapor of the organic silica compound supplied, as from a time of plasma ignition.
11. The method according to claim 10 , wherein
the organic silica compound is a cyclic organic silica compound including a skeleton composed by silicon, carbon and oxygen.
12. The method according to claim 10 , wherein
the organic silica compound is a cyclic organic silica compound including a skeleton composed by silicon, carbon and oxygen, with at least one unsaturated hydrocarbon group attached to its side chain.
13. A variable resistance element, comprising:
first and second electrodes; and
an ion conduction layer interposed between the first and second electrodes; wherein,
the ion conduction layer contains an organic oxide containing at least oxygen and carbon;
a carbon concentration distribution in the ion conduction layer being such that the carbon concentration in an area of the ion conduction layer closer to the first electrode is greater than that in an area thereof closer to the second electrode;
the carbon concentration distribution in the ion conduction layer decreases continuously or stepwise from the area on the first electrode side towards the area on the second electrode side: and
the ion conduction layer is a film containing at least silicon as element in addition to oxygen and carbon.
14. The variable resistance element according to claim 13 , wherein,
the ion conduction layer is a film containing an organic matter including a six-membered or eight-membered siloxane structure as a main skeleton.
15. The variable resistance element according to claim 14 , wherein,
the organic matter further includes at least an unsaturated hydrocarbon group.
16. The variable resistance element according to claim 14 , wherein
the ion conduction layer is a porous film.
17. The variable resistance element according to claim 13 , wherein
the ion conduction layer is a porous film.
18. The variable resistance element according to claim 13 , wherein
the ion conduction layer has a dielectric constant not less than 2.5 and not greater than 3.5.
19. The variable resistance element according to claim 13 wherein
the material of the first electrode comprises copper.
20. The variable resistance element according to claim 19 , further comprising:
a titanium oxide layer interposed between the ion conduction layer and copper of the first electrode, the ion conduction layer containing titanium.