Method of fabricating superconducting wire
A method of fabricating a superconducting wire includes forming a buffer layer on the substrate, the buffer layer including an Al 2 O 3 layer, the Al 2 O 3 layer being formed by reactive magnetron sputtering in which first oxygen gas as reactant gas and a sputtering target made of aluminium metal are used, the Al 2 O 3 layer being formed while being supplied the first oxygen gas at a first concentration, the first concentration being a concentration of the first oxygen gas at which an emission intensity of Al in plasma near a surface of the sputtering target is not less than 25% and not more than 80% of a first reference value, the first reference value being the emission intensity of Al at which the concentration of the first oxygen gas is zero; and forming a superconducting layer above the buffer layer.
1 . A method of fabricating a superconducting wire, comprising:
forming a buffer layer on the substrate, the buffer layer comprising an Al 2 O 3 layer, the Al 2 O 3 layer being formed by reactive magnetron sputtering in which first oxygen gas as reactant gas and a sputtering target made of aluminium metal are used, the Al 2 O 3 layer being formed while being supplied the first oxygen gas at a first concentration, the first concentration being a concentration of the first oxygen gas at which an emission intensity of Al in plasma near a surface of the sputtering target is not less than 25% and not more than 80% of a first reference value, the first reference value being the emission intensity of Al at which a concentration of the first oxygen gas is zero; and
forming a superconducting layer above the buffer layer.
2 . The method of fabricating a superconducting wire according to claim 1 , wherein
the first concentration is a concentration of the first oxygen gas at which an emission intensity of Al is not less than 30% and not more than 80% of the first reference value.
3 . The method of fabricating a superconducting wire according to claim 1 , wherein
the buffer layer comprises an Y 2 O 3 layer on the Al 2 O 3 layer, the Y 2 O 3 layer being formed by reactive magnetron sputtering in which second oxygen gas as reactant gas and a sputtering target made of yttrium metal are used, the Y 2 O 3 layer being formed while being supplied the second oxygen gas at a second concentration, the second concentration being a concentration of the second oxygen gas at which an emission intensity of Y in plasma near a surface of the sputtering target is not less than 15% and not more than 90% of a second reference value, the second reference value being the emission intensity of Y at which a concentration of the second oxygen gas is zero.
4 . The method of fabricating a superconducting wire according to claim 3 , wherein
the second concentration is the concentration of the second oxygen gas at which an emission intensity of Y is not less than 30% and not more than 80% of the second reference value.
5 . The method of fabricating a superconducting wire according to claim 3 , wherein
the buffer layer comprises an MgO layer having a biaxially textured structure on the Y 2 O 3 layer, the MgO layer being formed by reactive magnetron sputtering in which third oxygen gas as reactant gas and a sputtering target made of magnesium metal are used and assisting Ar ion beam is applied, the MgO layer being formed while being supplied the third oxygen gas at a third concentration, the third concentration being a concentration of the third oxygen gas at which an emission intensity of Mg in plasma near a surface of the sputtering target made of magnesium metal is less than 50% of a third reference value, the third reference value being an emission intensity of Mg at which a concentration of the third oxygen gas is zero.
6 . The method of fabricating a superconducting wire according to claim 3 , wherein
the buffer layer comprises an MgO layer having a biaxially textured structure on the Y 2 O 3 layer, the MgO layer being formed by magnetron sputtering in which a sputtering target made of MgO is used and assisting Ar ion beam is applied.
7 . The method of fabricating a superconducting wire according to claim 1 , wherein a process environment utilizes Ar and O 2 as a reactive gas.
8 . The method of fabricating a superconducting wire according to claim 7 ,
wherein the reactive magnetron sputtering comprises RF magnetron sputtering.
9 . The method of fabricating a superconducting wire according to claim 1 , further comprising controlling reactions in a transition area of reactive magnetron sputtering.
10 . The method of fabricating a superconducting wire according to claim 1 , wherein the first concentration being the concentration of the first oxygen gas at which the emission intensity of Al in plasma near the surface of the sputtering target is controlled to be not less than 25% and not more than 80% of the first reference value.
11 . A method of fabricating a superconducting wire, comprising:
forming a buffer layer on the substrate, the buffer layer comprising an Y 2 O 3 layer, the Y 2 O 3 layer being formed by reactive magnetron sputtering in which second oxygen gas as reactant gas and a sputtering target made of yttrium metal are used, the Y 2 O 3 layer being formed while being supplied the second oxygen gas at a second concentration, the second concentration being a concentration of the second oxygen gas at which an emission intensity of Y in plasma near a surface of the sputtering target is measured to be not less than 15% and not more than 90% of a first reference value, the first reference value being the emission intensity of Y at which a concentration of the first oxygen gas is zero; and
forming a superconducting layer above the buffer layer.
12 . The method of fabricating a superconducting wire according to claim 11 , wherein
the first concentration is a concentration of the first oxygen gas at which an emission intensity of Y is not less than 30% and not more than 80% of the second reference value.
13 . The method of fabricating a superconducting wire according to claim 11 , wherein
the buffer layer comprises an MgO layer having a biaxially textured structure on the Y 2 O 3 layer, the MgO layer being formed by reactive magnetron sputtering in which second oxygen gas as reactant gas and a sputtering target made of magnesium metal are used and assisting Ar ion beam is applied, the MgO layer being formed while being supplied the third oxygen gas at a second concentration, the second concentration being a concentration of the second oxygen gas at which an emission intensity of Mg in plasma near a surface of the sputtering target made of magnesium metal is less than 50% of a second reference value, the second reference value being the emission intensity of Mg at which the concentration of the second oxygen gas is zero.
14 . The method of fabricating a superconducting wire according to claim 11 , wherein
the buffer layer comprises an MgO layer having a biaxially textured structure on the Y 2 O 3 layer, the MgO layer being formed by magnetron sputtering in which a sputtering target made of MgO is used and assisting Ar ion beam is applied.
15 . The method of fabricating a superconducting wire according to claim 11 , wherein a process environment utilizes Ar and O 2 as a reactive gas.
16 . The method of fabricating a superconducting wire according to claim 15 ,
wherein the reactive magnetron sputtering comprises RF magnetron sputtering.
17 . The method of fabricating a superconducting wire according to claim 11 , further comprising controlling reactions in a transition area of reactive magnetron sputtering.
18 . A method of fabricating a superconducting wire, comprising:
forming a buffer layer on the substrate, the buffer layer comprising an MgO layer, the MgO layer being formed by reactive magnetron sputtering in which third oxygen gas as reactant gas and a sputtering target made of magnesium metal are used and to which ion beam assisted deposition is applied, the MgO layer being formed while being supplied the first oxygen gas at a first concentration, the first concentration being a concentration of the first oxygen gas at which an emission intensity of Mg in plasma near a surface of the sputtering target is measured to be less than 50% of a first reference value, the first reference value being an emission intensity of Mg at which the concentration of the first oxygen gas is zero; and
forming a superconducting layer above the buffer layer.
19 . The method of fabricating a superconducting wire according to claim 18 , wherein a process environment utilizes Ar and O 2 as a reactive gas, and
wherein the reactive magnetron sputtering comprises RF magnetron sputtering.
20 . The method of fabricating a superconducting wire according to claim 18 , further comprising controlling reactions in a transition area of reactive magnetron sputtering.