Title :
Miniaturized vortex transitional Josephson memory cell by a vertically integrated device structure
Author :
Nagasawa, S. ; Tahara, S. ; Numata, H. ; Tsuchida, S.
Author_Institution :
Fundamental Res. Labs., NEC Corp., Tsukuba, Japan
fDate :
3/1/1994 12:00:00 AM
Abstract :
We have developed the smallest Josephson nondestructive read-out (NDRO) memory cell, called a vortex transitional (VT) memory cell, for a Josephson high-speed 16-Kbit RAM. Its size is 22/spl times/22 /spl mu/m/sup 2/, which is only 16% of the size of previously developed VT memory cells used in Josephson 4-Kbit RAM. This is achieved by developing a vertically integrated device structure and refining small-junction technology. The cell consists of Nb/AlO/sub x//Nb junctions, three Nb wirings, SiO/sub 2/, insulators and Mo resistors. The VT memory cells operate properly, with a large operating margin of /spl plusmn/20%.<>
Keywords :
SQUIDs; aluminium compounds; niobium; random-access storage; superconducting memory circuits; 16 kbit; 22 micron; Josephson high-speed 16-Kbit RAM; Josephson nondestructive read-out memory cell; Mo; Mo resistors; Nb; Nb wirings; Nb-AlO-Nb; Nb/AlO/sub x//Nb junctions; SiO/sub 2/; SiO/sub 2/, insulators; VT memory cells; miniaturized vortex transitional Josephson memory cell; size; small-junction technology; vertically integrated device structure; Cache memory; Delay effects; Digital systems; Niobium; Power dissipation; Propagation delay; Random access memory; Read-write memory; Resistors; SQUIDs;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
