Fabrication of ultra-small and long intrinsic Josephson junctions on Bi-2212 single crystal whiskers

We report successful fabrication of small and long intrinsic Josephson junctions (IJJs) using Bi-2212 single crystal whiskers. The stacks of IJJs were made by 3-D focused-ion-beam (FIB) etching method. First a microbridge was patterned in a required junction width by etching into the substrate normal direction. By tilting the sample stage up to 90°, two grooves on the bridge were, then, etched from the lateral direction in order to create the required junction size. For in-plane area of 0.01 μm², Bi-2212 stacks showed no critical current. We also fabricated 3-D IJJs consisting of small and long stacks on the same chip