Method for fabricating a variable-resistance element including heating a RMCoO

1. A method for fabricating a variable-resistance element provided with a material layer and first and second electrodes electrically connected to the material layer, the resistance of the material layer being variable in accordance with an electric current or voltage applied across the first and second electrodes, the method comprising:

(1) a first electrode production step;

(2) a step of forming the material layer on the first electrode, wherein the material layer comprises an oxide semiconductor having a perovskite structure represented by the chemical formula RMCoO 3 , wherein R is a rare-earth element and M is an alkaline-earth element;

(3) an oxygen treatment step of heating the material layer in an oxygen atmosphere;

(4) a step of forming the second electrode on the material layer that was subjected to the oxygen treatment step; and

(5) a hydrogen treatment step of heating the material layer, which was subjected to the step of forming the second electrode, in a reducing atmosphere containing hydrogen.

2. A fabrication method according to claim 1 , wherein the oxide semiconductor having a perovskite structure is represented by the chemical composition formula Pr 1-x Ca x CoO 3 , wherein 0.4≦x≦0.6.

3. A fabrication method according to claim 1 , wherein the step of forming the material layer and the oxygen treatment step are repeated.

4. A fabrication method according to claim 1 , wherein the oxygen treatment step is a step of heating the material layer in an atmosphere containing at least one member selected from the group consisting of molecular oxygen (O 2 ), ozone (O 3 ), and atomic oxygen (O).

5. A fabrication method according to claim 1 , wherein the oxygen treatment step is a step of heating the material layer at 100 to 800° C.

6. A fabrication method according to claim 1 , wherein the oxygen treatment step is a step of heating the material layer for 30 minutes to 12 hours.