Tunnel-type Josephson element and method for manufacturing the same

Abstract

A plurality of single crystal grains made of Bi.sub.2 Sr.sub.2 Ca.sub.1 Cu.sub.2 O.sub.8 which are heat treated at a temperature that is equal to or higher than the crystallization temperature of an oxide high-temperature superconductor made of Bi.sub.2 Sr.sub.2 Ca.sub.1 Cu.sub.2 O.sub.8 and are surrounded by a grain boundary are formed on a substrate made of a MgO single crystal. A convex portion having a sectional area of 400 .mu.m.sup.2 or less and a height which is equal to or less than ten times as much as a space between block layers of Bi.sub.2 Sr.sub.2 Ca.sub.1 Cu.sub.2 O.sub.8 is formed on the upper face portion of the single crystal grain. A first electrode made of Au is formed on the upper face of the convex portion of the single crystal grain, and a second electrode is formed in a region other than the convex portion in the single crystal grain. The first electrode is insulated from the second electrode by an insulating film made of CaF.sub.2.

Dependencies are inferred from the claim text.