Submicron stacked-junction fabrication from Bi2Sr2CaCu2O8+δ whiskers by focused-ion-beam etching

We fabricated submicron-sized intrinsic Josephson junctions by the focused-ion- beam (FIB) etching method. The principal result was a reduction of the in-plane junction area to 0.3 mu m(2) by direct FIB etching with no degradation in the critical transition temperature (Tc). In the current (I)-voltage (V) characteristics of these stacks, the gap structure and the normal state resistance are clearly observed together with a reduction of the Joule heating and disappearance of the branch structure. The Coulomb staircase structure was found in the I - V curves of submicron junctions as a result of their small effective capacitance of fF order. (C) 1999 American Institute of Physics. [S0003-6951(99)01508-9].