Electro-resistance element, electro-resistance memory using the same and method of manufacturing the same
View Patent ↗An electro-resistance element that has a different configuration from conventional elements and is excellent in both affinity with semiconductor manufacturing processes and resistance change characteristics is provided. An electro-resistance element has two or more states in which electric resistance values between a pair of electrodes and is switchable from one of the two or more states into another by applying a predetermined voltage or current between the electrodes. The electro-resistance element includes a substrate and a multilayer structure disposed on the substrate, the multilayer structure includes an upper electrode, a lower electrode and an electro-resistance layer disposed between the electrodes, wherein the electro-resistance layer includes Fe 2 O 3 , and Fe 3 O 4 contained in an amount of 0% to 20% of Fe 2 O 3 in percent by weight, the lower electrode is made of an iron oxide having a different composition from the electro-resistance layer and containing Fe 3 O 4 , and the electro-resistance layer and the lower electrode make contact with each other.
1. An electro-resistance element, comprising:
a substrate; and
a multilayer structure disposed on the substrate,
the multilayer structure including an upper electrode, a lower electrode, and an electro-resistance layer disposed between the upper and the lower electrodes,
the electro-resistance element having two or more states in which electric resistance values between the upper and the lower electrodes are different, and
being switchable from one of the two or more states into another by applying a predetermined voltage or current between the upper and the lower electrodes,
wherein the electro-resistance layer includes Fe 2 O 3 , and
an amount of Fe 3 O 4 contained in the electro-resistance layer is 0% to 20% of an amount of Fe 2 O 3 in percent by weight,
the lower electrode is made of an iron oxide containing Fe 3 O 4 , and having a different composition from the electro-resistance layer, and
the electro-resistance layer and the lower electrode make contact with each other.
2. The electro-resistance element according to claim 1 , wherein the lower electrode consists essentially of Fe 3 O 4 .
3. The electro-resistance element according to claim 1 , wherein the electro-resistance layer consists essentially of an iron oxide.
4. The electro-resistance element according to claim 1 , wherein the lower electrode consists essentially of Fe 2 O 3 and Fe 3 O 4 .
5. The electro-resistance element according to claim 1 , wherein the lower electrode consists essentially of Fe 2 O 3 .
6. The electro-resistance element according to claim 1 , wherein the predetermined voltage or current is in a pulse form.
7. An electro-resistance memory, comprising two or more of the electro-resistance element according to claim 1 as a memory element.
8. The electro-resistance memory according to claim 7 , wherein the two or more of the electro-resistance elements are arranged in a matrix form.
9. A method of manufacturing the electro-resistance element according to claim 1 , comprising:
forming a lower electrode made of an iron oxide containing Fe 3 O 4 on a substrate;
forming an electro-resistance layer having a different composition from the iron oxide, and including Fe 2 O 3 and Fe 3 O 4 contained in an amount of 0% to 20% of Fe 2 O 3 in percent by weight, on the lower electrode to make contact with each other; and
forming an upper electrode sandwiching the electro-resistance layer with the lower electrode.
10. The method of manufacturing the electro-resistance element according to claim 9 , wherein the iron oxide consists essentially of Fe 3 O 4 .
11. The method of manufacturing the electro-resistance element according to claim 9 , wherein the iron oxide is Fe304, an electro-resistance layer made of an iron oxide is formed in the forming an electro-resistance layer step, an identical raw material containing iron and oxygen is used in the forming a lower electrode step and the forming an electro-resistance layer step, and a ratio P oxy /P inert between partial pressure P inert of an inert gas and partial pressure P oxy of oxygen in an atmosphere in the forming an electro-resistance layer step is made larger than a ratio in an atmosphere in the forming a lower electrode step.
12. The method of manufacturing the electro-resistance element according to claim 11 , wherein the raw material has a composition represented by a formula FeOx (1/2<=x<4/3).
13. The method of manufacturing the electro-resistance element according to claim 9 ,
wherein the iron oxide is Fe 3 O 4 , and
the electro-resistance layer made of an iron oxide is formed by oxidizing a surface of the lower electrode in the forming an electro-resistance layer step.
14. The method of manufacturing the electro-resistance element according to claim 9 , wherein an electro-resistance layer consisting essentially of an iron oxide is formed in the forming an electro-resistance layer step.
15. The method of manufacturing the electro-resistance element according to claim 9 , wherein an electro-resistance layer consisting essentially of Fe 2 O 3 and Fe 3 O 4 is formed in the forming an electro-resistance layer step.
16. The method of manufacturing the electro-resistance element according to claim 9 , wherein an electro-resistance layer consisting essentially of Fe 2 O 3 is formed in the forming an electro-resistance layer step.