Study of in-situ prepared high-temperature superconducting edge-type Josephson junctions

High-T/sub c/ edge-type Josephson junctions usually have ex-situ interfaces, that probably contain damaged layers caused by etching process and/or by exposure to air. The ex-situ interface layer may be an origin of poor reproducibility and uniformity of the device characteristics, as well as an excess interface resistance and a suppression of the critical current. We have developed an in-situ edge preparation process to improve the uniformity and electrical characteristics of the edge junctions. In our in-situ process, the base YBaCuO electrode edge is not exposed to air after the preparation of the edge and subsequently followed by the deposition of a barrier layer and a counter electrode. The in-situ YBaCuO/PrBaCuO/YBaCuO junctions showed larger critical current density (J/sub c/) and normal state conductance (G/sub n/) than the ex-situ junctions. In addition, smaller J/sub c/ and G/sub n/ spreads have been obtained for the in-situ junctions.