Applied Physics Letters · 1993 · 28 citations · 4 references
Natural SciencesElectrical EngineeringPhysicsCondensed Matter PhysicsElectronic MaterialsMicrofabricationHigh-frequency Semiconductor DevicesMicrowave Integrated CircuitsNoise In Electronic DevicesSemiconductor PhysicsSuperconducting MaterialsSuperconducting Thin FilmsDevice FabricationOptical Lithography
High-current density, submicron-sized superconductor-insulator-superconductor niobium junctions are made with optical lithography. With a novel process junctions as small as 0.8 μm2 are routinely made using a controlled under-etch with the quality parameter Vm up to 67 mV. The junction quality is found to be independent of the amount of under-etch. Used in a 345 and 490 GHz waveguide mixer, noise temperatures have been obtained as low as 131 K double-side band (DSB) and 120 K (DSB), respectively.
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