Fabrication of all YBaCuO trilayer Josephson junctions with YBaCuO wiring layer

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. CeO/sub 2/ films (520nm) and YBaCuO films (1.2 /spl mu/m) were used as insulating layers and wiring layers, respectively. A junction with a dimension of 7 /spl mu/m/spl times/7 /spl mu/m showed a critical current I/sub c/ of 1.6 mA and a junction resistance R/sub n/ of 1.2 /spl Omega/ at 4.2 K. The values of the critical current density and the I/sub c/R/sub n/ product were estimated to be 3.3kA/cm/sup 2/ and 1.9 mV, respectively. Note that the junction exhibited I/sub c/R/sub n/ 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.