Dynamic study and experimental "two-step process" of substrate step preparation for high-T-c Josephson junctions

We report theoretical and experimental studies of the dynamics of substrate step preparation for high-T-c Josephson junctions. A maximum step edge ang le of 70.8 degrees has been calculated for SrTiO3 (STO) substrates with a N b mask. This calculated angle agrees well with our experimental result of 6 6 degrees. Step-edge angles can be predicted for different purposes using t his method. We also utilized a "two-step process" to improve the surface mo rphology of the stepped substrate, and step-edge Josephson junctions were f abricated with good uniformity. (C) 2000 American Institute of Physics. [S0 003-6951(00)04010-9].