Fabrication of Intrinsic Josephson Junctions on Bi₂Sr₂CaCu₂O_8+δ Single Crystals with Reproducible Surface Junctions

Intrinsic Josephson junctions on Bi₂Sr₂CaCu₂O_8+δ single crystals are successfully fabricated using photolithography and Ar ion milling. Here we discuss the properties of the surface CuO₂/metal bilayers and surface junctions prepared with different crystal cleavage conditions and metal film deposition techniques. We show that by cleaving the crystal at liquid nitrogen temperature in vacuum, the contents of the (interstitial) oxygen in the Bi-O layers become stable upon cleavage, leading to a CuO₂/metal bilayer and to surface junctions with reproducible properties. These results can be useful for practical device fabrications as well as for the studies of the contact properties between high T_c superconductors and normal metals.