2 research outputs found
Improving Josephson junction reproducibility for superconducting quantum circuits: junction area fluctuation
Josephson superconducting qubits and parametric amplifiers are prominent
examples of superconducting quantum circuits that have shown rapid progress in
recent years. With the growing complexity of such devices, the requirements for
reproducibility of their electrical properties across a chip have become
stricter. Thus, the critical current variation of the Josephson junction,
as the most important electrical parameter, needs to be minimized. Critical
current, in turn, is related to normal-state resistance the Ambegaokar-Baratoff
formula, which can be measured at room temperature. Here, we focus on the
dominant source of Josephson junction critical current non-uniformity junction
area variation. We optimized Josephson junctions fabrication process and
demonstrate resistance variation of and across
and chip areas, respectively. For a
wide range of junction areas from to we
ensure a small linewidth standard deviation of measured over 4500
junctions with linear dimensions from to . The developed process
was tested on superconducting highly coherent transmon qubits and a nonlinear asymmetric inductive element parametric
amplifier