  A reliable process has been developed for the fabrication of all-Nb
single-electron circuits, based on spin-on glass planarization. The process
steps are the in situ growth of Nb/AlOx/Nb sandwich, definition of the patterns
of junctions, base electrodes and wiring by use of reactive ion etching and the
planarization of a spin-on glass insulation between base electrode and wiring.
A single electron transistor made of 0.1 square micrometer area junctions
clearly shows the e-periodic Coulomb blockade modulation by a voltage applied
to a gate.

Mesoscale and Nanoscale Physics;Superconductivity