DC-SQUIDs fabricated by electron beam direct writing

An Electron Beam MicroFabricator (EBMF) has been used to write directly on a silicon wafer to obtain many equal chips containing dc-SQUIDs and superconducting test circuitry. We developed a complete lift-off technique on an electronic resist for all the seven needed layers of the process. The first layer, consisting of Au-Pd alloy, is used as resistor and for patterning the markers required to align the various layers. The calibration on such markers avoid the stitching problem due to the large chip dimensions (6.30× 6.30 mm) as ...