Josephson junctions with reduced stray inductance

A method comprising:

• providing a substrate comprising a first resist layer patterned to include an opening region that exposes a surface of the substrate, wherein the opening region is laterally enclosed on all sides by the first resist layer;
• depositing a first superconductor material on the patterned first resist layer at a first non-normal angle with respect to the substrate along a first direction to form a first superconductor layer within the opening region, wherein the patterned first resist layer blocks the first superconductor layer from forming in at least a first part of the opening region;
• forming an insulator layer on a portion the first superconductor layer;
• depositing a second superconductor material on the insulator layer and the patterned first resist layer at a second non-normal angle with respect to the substrate along a second direction to form a second superconductor layer within the opening region, wherein the patterned first resist layer blocks the second superconductor layer from forming in at least a second part of the opening region, and wherein the first superconductor layer, the insulator layer, and the second superconductor layer within the opening region provide a superconductor tunnel junction;
• and
• forming a third superconductor layer directly on a surface of the first superconductor layer and directly on a surface of the second superconductor layer to provide a first contact to the superconducting tunnel junction and a separate second contact to the superconductor tunnel junction, respectively.

A device comprising:

• a substrate;
• a first superconductor layer on the substrate;
• an insulator layer on the first superconductor layer;
• a second superconductor layer on the insulator layer, wherein the first superconductor layer, the insulator layer, and the second superconductor layer form a superconductor tunnel junction;
• and
• a third superconductor layer directly on a surface of the first superconductor layer and directly on a surface of the second superconductor layer to provide a first contact to the superconducting tunnel junction and a second contact to the superconductor tunnel junction, respectively,
• wherein the first superconductor layer comprises i) a first portion that forms a bottom electrode to the superconductor tunnel junction and ii) a second portion directly adjacent to the bottom electrode, wherein the first contact is formed directly on the second portion of the first superconductor layer and wherein the second portion of the first superconductor layer comprises a corresponding wide section and a corresponding narrow section having a length extending outwardly from the wide section of the first superconductor layer, and
• wherein the second superconductor layer comprises i) a first portion that forms a top electrode to the superconductor tunnel junction and ii) a second portion directly adjacent to the top electrode, wherein the second contact is formed directly on the second portion of the second superconductor layer and wherein the second portion of the of the second superconductor layer comprises a corresponding wide section and a corresponding narrow section having a length extending outwardly from the wide section of the second superconductor layer.