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

We have demonstrated a new planarized all‐refractory technology for low Tc superconductivity (PARTS). With the exception of the Nb‐AlOx‐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.