Method of fabrication of Josephson tunnel junction
AssigneeNippon Telegraph & Telephone Public Corporation
InventorsOsamu Michikami, Yujiro Katoh, Keiichi Tanabe, Hisataka Takenaka, Shizuka Yoshii
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Abstract
There is disclosed a method of fabrication of a Josephson tunnel junction device. A surface of a base electrode of Nb or Nb compound is subjected to sputter cleaning and then to plasma oxidation in an atmosphere of a diluent gas and oxygen to form thereon an oxide layer serving as a tunnel barrier. A counter electrode is then formed on the oxide layer to provide the Josephson tunnel junction.
Claims30
A method for the fabrication of a Josephson tunnel junction device which comprises the steps of:
- (a) forming a base electrode film of a first superconductor metal on a substrate;
- (b) subjecting a surface of the base electrode film to sputter cleaning in the presence of a halogenated hydrocarbon selected from the group consisting of fluorinated hydrocarbons (CnF.sub.2n+2 :n=1.about.4), trifluoromethane (CHF.sub.3), trichlorofluoroethane (CCl.sub.3 F), trifluorobromomethane (CBrF.sub.3), dichlorodifluoromethane (CCl.sub.2 F.sub.2), trifluoroethane (C.sub.2 H.sub.3 F.sub.3) and pentafluoroethane (C.sub.2 HF.sub.5);
- (c) oxidizing the cleaned surface of the base electrode in the presence of a gas mixture of oxygen and inert gas to form an oxide layer on the base electrode;
- and
- (d) forming a counter electrode film of a second superconductor metal on the oxide layer.
A method for the fabrication of a Josephson tunnel junction device which comprises the steps of:
- (a) forming a base electrode film of a first superconductor metal on a substrate;
- (b) subjecting a surface of the base electrode film to sputter cleaning in the presence of a diluent gas and a halogenated hydrocarbon selected from the group consisting of fluorinated hydrocarbons (CnF.sub.2n+2 :n=1.about.4), trifluoromethane (CHF.sub.3), trichlorofluoromethane (CCl.sub.3 F), trifluorobromomethane (CBrF.sub.3), dichlorodifluoromethane (CCl.sub.2 F.sub.2), trifluoroethane (C.sub.2 H.sub.3 F.sub.3), and pentafluoroethane (C.sub.2 HF.sub.5);
- (c) oxidizing the cleaned surface of the base electrode in the presence of a gas mixture of oxygen and inert gas to form an oxide layer on the base electrode;
- and
- (d) forming a counter electrode film of a second superconductor metal on the oxide layer.
A method for the fabrication of a Josephson tunnel junction device which comprises the steps of:
- (a) forming a base electrode film of a first superconductor metal on a substrate;
- (b) subjecting a surface of the base electrode film simultaneously to sputter cleaning and oxidation in the presence of a gas mixture of a diluent gas, oxygen, and a halogenated hydrocarbon selected from the group consisting of fluorinated hydrocarbons (CnF.sub.2n+2 :n=1.about.4), trifluoromethane (CHF.sub.3), trichlorofluoromethane (CCl.sub.3 F), trifluorobromomethane (CBrF.sub.3), dichlorodifluoromethane (CCl.sub.2 F.sub.2), trifluoroethane (C.sub.2 H.sub.3 F.sub.3) and pentafluoroethane (C.sub.2 HF.sub.5), so that an oxide layer is formed on the base electrode;
- and
- (c) forming a counter electrode film of a second superconductor metal on the oxide layer.
Dependencies are inferred from the claim text.