Physical and technological limitations of SNS Josephson junctions for large scale integration low temperature superconductor circuits

Future demands on superconductive microelectronic circuits call for a high scale of integration, which requires small line width and, at the same time, ultra high speed data processing. Digital superconducting electronics are widely regarded as a good candidate for future applications. In this field, Rapid Single Flux Quantum (RSFQ)-logic in low temperature implementation plays a significant roll. RSFQ-logic is attractive essentially because of two physical and technical phenomena which are not found in other implementations, namely ultra short switching times in the pico second range and, simultaneously, extremely small power dissipation (< 1µW/gate). Very fast information processing up to the sub-tera Hertz range can be achieved.