Fabrication of all YBaCuO trilayer Josephson junctions with YBaCuO wiring layer

摘要

We report a fabrication process of c-axis oriented all YBaCuO trilayer Josephson junctions with YBaCuO wiring layers. The trilayer junctions consisted of YBaCuO (170nm)/PrBaCuO (28 nm)/YBaCuO (170 nm) structures. CeO2 films (520nm) and YBaCuO films (1.2 μm) were used as insulating layers and wiring layers, respectively. A junction with a dimension of 7 μm×7 μm showed a critical current Ic of 1.6 mA and a junction resistance Rn of 1.2 Ω at 4.2 K. The values of the critical current density and the IcRn product were estimated to be 3.3kA/cm2 and 1.9 mV, respectively. Note that the junction exhibited IcRn product of 1.0 mV even at 30 K. From these results, the junction is promising candidate for satisfying the requirements for HTS integrated circuits.