Superconducting readout of semiconductor memory at liquid nitrogen temperature

The discovery of high-temperature superconducting materials raises the possibility of operating semiconducting and superconducting circuits at the same temperature in intimately hybridized devices and circuits. We report the experimental readout of standard CMOS memory cells using high-temperature superconducting flux flow devices at 77 K. Significant reduction in access times below that achievable with cryogenic CMOS alone was measured; a 4.5-ns access time was achieved on a 1-μm CMOS static random access memory. These results obtained using nonoptimized, separate superconductor, and semiconductor chips demonstrate the potential of hybrid superconductor-semiconductor memories for speed and power improvements over pure semiconductors operated at cryogenic temperatures.