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US 5,477,061 AGranted
Josephson device having an overlayer structure with improved thermal stability
AssigneeFujitsu Limited
InventorShinichi Morohashi
Life of this patent
Estimating the term…
Abstract
A Josephson device comprises a first electrode layer of a superconducting material and containing Nb therein as a constituent element, an overlayer of a nitride of a refractory metal element provided on the first electrode layer, a barrier layer of an insulating compound that contains the metal element as a constituent element and acting as a barrier of a Josephson junction, the barrier layer being provided on the overlayer, and a second electrode layer of a superconducting material and containing Nb therein as a constituent element, the second electrode layer being provided on the barrier layer.
Claims14
A Josephson device, comprising:
- a first electrode layer of a superconducting material containing Nb as a constituent element, said first electrode layer having upper and lower major surfaces;
- an overlayer of a nitride of a metal element, said overlayer having upper and lower major surfaces and being provided on the first electrode layer;
- a barrier layer of an insulating material containing said metal element as a constituent element and acting as a barrier layer of a Josephson junction, said barrier layer having upper and lower major surfaces and being provided on said upper major surface of said overlayer;
- a second electrode layer of a superconducting material containing Nb therein as a constituent element, said second electrode layer having upper and lower major surfaces and being provided on said upper major surface of said barrier layer;
- each of said first and second electrode layers having a coherent length and said overlayer having a thickness, measured between the upper and lower major surfaces thereof, which is less than said coherent length;
- and
- said nitride of said metal element, of said overlayer, consisting essentially of ZrN, and said insulting material of said barrier layer consisting essentially of Zro.sub.x.
4 more elements
A Josephson device, comprising:
- a first electrode layer of a superconducting material containing Nb as a constituent element, said first electrode layer having upper and lower major surfaces;
- an overlayer of a nitride of a metal element, said overlayer having upper and lower major surfaces and being provided on the first electrode layer;
- a barrier layer of an insulting material containing said metal element as a constituent element and acting as a barrier layer of a Josephson junction, said barrier layer having upper and lower major surfaces and being provided on said upper major surface of said overlayer;
- a second electrode layer of a superconducting material containing Nb therein as a constituent element, said second electrode layer having upper and lower major surfaces and being provided on said upper major surface of said barrier layer;
- each of said first and second electrode layers having a coherent length and said overlayer having a thickness, measured between the upper and lower major surfaces thereof, which is less than said coherent length;
- and
- said nitride of said metal element, of said overlayer, consisting essentially of TaN, and said insulating material of said barrier layer consisting essentially of TaO.sub.x.
4 more elements
A Josephson device as claimed in claim, in which said overlayer has a thickness of less than 10 nm.
A Josephson device, comprising:
- a first electrode layer of a superconducting material containing Nb as a constituent element, said first electrode layer having upper and lower surfaces;
- an overlayer of a nitride of a metal element, said overlayer having upper and lower major surfaces and being provided on the first electrode layer;
- a barrier layer of an insulting material containing said metal element as a constituent element and acting as a barrier layer of a Josephson junction, said barrier layer having upper and lower major surfaces and being provided on said upper major surface of said overlayer;
- a second electrode layer of a superconducting material containing Nb therein as a constituent element, said second electrode layer having upper and lower major surfaces and being provided on said upper major surface of said barrier layer;
- each of said first and second electrode layers having a coherent length and said overlayer having a thickness, measured between the upper and lower major surfaces thereof, which is less than said coherent length;
- and
- said nitride of said metal element, of said overlayer, consisting essentially of TaN and said insulating material of said barrier layer consisting essentially of Ta.sub.2 N.
4 more elements
Dependencies are inferred from the claim text.