A kinetic-inductance-based superconducting memory element with shunting and sub-nanosecond write times
Adam N. McCaughan, Michael L. Schneider, Sae Woo Nam, Emily Toomey, Karl Berggren
We present a kinetic-inductance-based superconducting memory element that had non-destructive readout, femtojoule read and write energies, had both read and write shunts, and was writeable with pulses at least as short as 400 ps. The element utilizes both a high-kinetic-inductance layer made from tungsten silicide as well as a low-kinetic-inductance layer made from niobium. By using tungsten silicide--which has a long (20 ns) thermal time constant--and measuring bit- error rates from 10 MHz to 1 GHz, we were able to verify that the thin-film elements could be operated at a datarate at least as fast as the material thermal time constant with a bit error ratio less than 10-6. We also analyze the margins of the device, and outline the characteristics by which a more efficient device may be designed.