Sub-μm, planarized, Nb-AlO_x-Nb Josephson process for 125 mm wafers developed in partnership with Si technology

Abstract

We have demonstrated a new planarized all-refractory technology for low Tc superconductivity (PARTS). With the exception of the Nb-AlO x-Nb trilayer preparation, the processing is done almost exclusively within an advanced Si technology fabrication facility. This approach has allowed us to leverage highly off of existing state-of-the-art lithography, metal etching, materials deposition, and planarization capabilities. Using chemical-mechanical polish as the planarization technique we have fabricated Josephson junctions ranging in size from 0.5-100 μm2. Junction quality is excellent with the figure of merit Vm typically exceeding 70 mV. PARTS has yielded fully functional integrated Josephson devices including magnetometers, gradiometers, and soliton oscillators.