S-N-S weaklink junctions fabricated by nanometer lithography

It is well known that the dimensions of the weak-link is the most important factor of its characteristics. However, the relationship between the dimensions and the characteristics of the weak-links are not clarified, because the geometrical dimensions are usually different from the effective dimensions, To clarify this relationship, we fabricated S-N-S (niobium as the superconductor and gold as the normal metal) weak-link junctions using electron beam lithography (EBL), reactive ion etching (RIE) and lift-off. The dimensions of the weak-links were controllable and the minimum width and length were 30 nm and 40 nm, respectively,.