Superconductor-semiconductor memories

The authors describe new types of hybrid superconductor-semiconductor RAMs which utilize the current switches in superconductive electronics to remove important constraints on the design of semiconductor memories and achieve performances attainable by the individual technologies separately. They focus on a voltage word line RAM architecture and illustrate the basic designs in terms of a low-T/sub c/ Josephson-CMOS technology. They discuss the design of interface circuits, word-line drivers, memory cells, and fluxoelectronic current sensing of bit lines. Current projections for 4 K operation indicate that sub-nanosecond 64-kb RAMs using a 0.8- mu m CMOS technology are possible. Extensions of this design to high-T/sub c/ superconductor-CMOS circuits operating at 77 K are briefly discussed.<>