Title :
Physics of high jc Nb/AlOx/Nb Josephson junctions and prospects of their applications
Author :
Naveh, Yehuda ; Averin, Dmitri V. ; Likharev, Konstantin K.
Author_Institution :
IBM, Haifa, Israel
fDate :
3/1/2001 12:00:00 AM
Abstract :
At critical current density of the order of 100 kA/cm2, tunnel Josephson junctions become overdamped and may be used in RSFQ circuits without external shunting, dramatically increasing circuit density. However, the physics of electron transport in such high-jc junctions differs from the usual direct tunneling and until recently remained unclear. We have found that the observed dc I-V curves of niobium-trilayer junctions with jc=210 kA/cm2 can be explained quantitatively by resonant tunneling through strongly disordered barriers. According to this interpretation, random spread of critical current in high-jc junctions may be rather small (below 1% r.m.s.) even in deep-submicron junctions, making VLSI RSFQ circuits, with density above 10 MJJ/cm2, feasible
Keywords :
Josephson effect; aluminium compounds; critical current density (superconductivity); niobium; resonant tunnelling; superconducting integrated circuits; DC I-V characteristics; Nb-AlO-Nb; Nb/AlOx/Nb Josephson junction; VLSI RSFQ circuit; critical current density; disordered barrier; electron transport; niobium trilayer junction; resonant tunneling; superconducting digital electronics; Critical current; Critical current density; Integrated circuit technology; Josephson junctions; Niobium; Physics; Superconducting integrated circuits; Superconducting logic circuits; Tunneling; Voltage;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
