HIGH-TEMPERATURE SUPERCONDUCTING SHIFT REGISTERS OPERATING AT UP TO 100 GHZ

Shift registers have been demonstrated in YBaCuO operating at 77 K usi ng from 64 to over 1600 junctions. These are some of the larger scale integrated circuits demonstrated to date using YBaCuO Josephson techno logy. The circuit is a modified rapid single flux quantum design in wh ich a single trigger pulse causes a one bit shift of the entire word o f 32-512 b in length. Two different junction technologies, electron-be am defined nanobridges and epitaxial edge junctions, have been used wi th parameter spreads ranging from 11% to 22%. Correct operation has be en verified with low speed random word tests and circulating data test s while pseudo random bit sequence demonstrations are underway. A prac tical amount of time to shift between cells has been measured to be ab out 10 ps.