Logic gates using stacked Josephson junctions

We investigate the possibility of making ultrafast superconducting logic gates using vertically stacked Josephson junctions. Employing flux quanta as information bits, we implement the functions of the logic gates AND, OR and EX-OR. Other logic functions and memory elements can be made by properly configuring these elementary logic gates. Design of these devices exhibits wide tolerance and flexibility in selecting the geometrical and electrical parameters. (C) 1999 Elsevier Science B.V. All rights reserved.