Production method of electroconductive mayenite compound having high electron density, and target

1. A production method of an electroconductive mayenite compound having an electron density greater than or equal to 5×10 20 cm −3 , comprising:

preparing an object of processing containing a mayenite compound or a precursor of the mayenite compound;

placing aluminum foil on at least a part of a surface of the object of processing; and

retaining the object of processing at a temperature falling within a range of 1080° C. to 1450° C. in a low oxygen partial pressure atmosphere.

2. The production method as claimed in claim 1 , wherein a total thickness of the aluminum foil falls within a range of 5 μm to 1000 μm.

3. The production method as claimed in claim 1 , wherein

the object of processing includes a bottom surface that becomes a lowermost surface in a vertical direction when the object of processing is placed, and

the aluminum foil is placed on the bottom surface of the object of processing in said placing.

4. The production method as claimed in claim 3 , wherein

the object of processing includes a top surface opposite to the bottom surface, and

the aluminum foil is placed on the top surface of the object of processing in said placing.

5. The production method as claimed in claim 1 , wherein the aluminum foil is placed on an entire surface of the object of processing in said placing.

6. The production method as claimed in claim 1 , wherein the low oxygen partial pressure atmosphere contains carbon monoxide gas.

7. The production method as claimed in claim 1 , wherein said placing and said retaining are performed with the object of processing being placed inside a carbon-containing container.

8. The production method as claimed in claim 1 , wherein the object of processing is a forming body including a powder of the mayenite compound, a sintered body including the mayenite compound, or a forming body including a calcined powder.

9. The production method as claimed in claim 1 , wherein the object of processing contains a halogen component.

10. The production method as claimed in, claim 1 , wherein said placing and said retaining are performed in an environment where a pressure is reduced to less than or equal to 100 Pa or in an atmosphere of an inert gas other than nitrogen.

11. The production method as claimed in claim 1 , wherein the electroconductive mayenite compound having a minimum size of 5 mm or more is obtained after said retaining.

12. A method of producing a target for film deposition that includes an electroconductive mayenite compound having an electron density greater than or equal to 0.5×10 20 cm −3 , the method comprising:

preparing an object of processing containing a mayenite compound or a precursor of the mayenite compound;

placing aluminum foil on at least a part of a surface of the object of processing; and

retaining the object of processing at a temperature of from 1080° C. to 1450° C. in a low oxygen partial pressure atmosphere.