Improved Nb-Si-Nb SNAP devices

We have compared the tunneling characteristics of Nb-Si-Nb junctions whose amorphous silicon barriers have been sputtered in pure Ar with those sputtered Ar-H 2 plasmas as well as in various combinations. We observe lower subgap currents with composite barriers which comprise a central region which is hydrogenated but which is sandwiched between two thin unhydrogenated layers. The improved tunneling characteristics may be associated with the lower density of localized states in the hydrogenated silicon.

[1]  M. Nisenoff,et al.  High quality niobium nitride-niobium Josephson tunnel junctions , 1983 .

[2]  H. Kroger,et al.  All-refractory Josephson logic circuits , 1983, IEEE Journal of Solid-State Circuits.

[3]  L. Smith,et al.  Sputtered a-silicon tunneling barriers for Nb-Nb Josephson junctions , 1982 .

[4]  M. Nisenoff,et al.  Niobium nitride‐niobium Josephson tunnel junctions with sputtered amorphous silicon barriers , 1982 .

[5]  A. Shoji,et al.  Josephson Tunnel Junctions with Nb, NbN Double-Layered Electrodes , 1982 .

[6]  D. Anderson,et al.  Properties of amorphous hydrogenated silicon, with special emphasis on preparation by sputtering , 1981 .

[7]  A. Shoji,et al.  Tunneling Characteristics of NbN/NbN Josephson Junctions with Glow-Discharge-Produced Amorphous Silicon Barriers , 1981 .

[8]  L. Smith,et al.  Selective niobium anodization process for fabricating Josephson tunnel junctions , 1981 .

[9]  A. Shoji,et al.  Niobium nitride Josephson tunnel junctions with oxidized amorphous silicon barriers , 1981 .

[10]  M. Beasley,et al.  Oxidized amorphous‐silicon superconducting tunnel junction barriers , 1980 .

[11]  J. Halbritter.  On surface states at superconductor oxide interfaces , 1980 .

[12]  R. F. Broom,et al.  Fabrication and Properties of Niobium Josephson Tunnel Junctions , 1980, IBM J. Res. Dev..

[13]  P. Seidel,et al.  A direct calculation of the resonance tunneling in metal–insulator–metal tunnel junctions , 1977 .

[14]  A. Yoshida,et al.  The effects of annealing on mott's parameters for hopping conduction in amorphous Ge , 1977 .

[15]  J. Rowell,et al.  Superconductive tunneling into niobium-tin thin films , 1976 .

[16]  J. Rowell,et al.  Zero-Bias Tunneling Anomalies-Temperature, Voltage, and Magnetic Field Dependence , 1968 .

[17]  J. Appelbaum.  Exchange Model of Zero-Bias Tunneling Anomalies , 1967 .

[18]  P. Anderson.  LOCALIZED MAGNETIC STATES AND FERMI-SURFACE ANOMALIES IN TUNNELING , 1966 .

[19]  L. Smith,et al.  A NOVEL PROCESS FOR FABRICATING JOSEPHSON TUNNEL JUNCTIONS , 1982 .

[20]  P. Nagels.  Electronic transport in amorphous semiconductors , 1979 .

[21]  H. Kroger,et al.  Niobium Josephson junctions with doped amorphous silicon barriers , 1979 .