Fabrication of ramp-edge Josephson junction by PLD method using double plume

Abstract Fabrication of high- T c ramp-edge Josephson junctions with interface-modified barriers in a wide area have been studied. A novel pulsed laser deposition apparatus with a double laser plume was newly designed. We succeeded in observing RSJ I – V characteristics with an excess current ratio as low as approximately 15% for all junctions dispersively located on a chip with a size of 15 × 15 mm 2 . It was found that the characteristics of the junctions significantly depend on the geometric configuration of the laser plume and the ramps during counter-layer deposition.