YBCO Josephson Junctions and Striplines for RSFQ Circuits Made by Ion Irradiation

We have investigated the electrodynamic properties of high-Tc Josephson junctions (JJs) and striplines made by ion irradiation in order to evaluate the potential of such a technology for low-power rapid single flux quantum superconductor digital electronics. The process is briefly presented, together with the JJ characteristics in the context of high-speed electronics. Line inductances of different geometries and at different temperatures have been measured through superconducting quantum interference device (SQUID) modulation. A detailed comparison with 3-D numerical calculations has been made, and a quantitative agreement that shows typical values of 4-8 pH per square without a ground plane, depending on linewidth and the gap to the ground line, has been obtained.