A fast turn-around time process for fabrication of qubit circuits

The authors describe a process for fabrication of Nb/AlO_x/Nb Josephson junction circuits for quantum computation. The process involves only one etch step and incorporates electron beam lithography and a self-aligned lift-off of the dielectric resulting in a short turn-around time of 4-5 days. Deep submicron junctions of size down to 0.15 × 0.15 μm² have been fabricated and tested. Results of junction quality measurements will be presented. In particular, a subgap resistance of ∼1 GΩ measured at ∼0.4 K indicates that the junction´s subgap leakage should not be a limitation for quantum computation.