  Niobium thin film wires were fabricated using electron beam lithography with
a four layer liftoff mask system, and subsequently thinned by anodisation. The
resistance along the wire was monitored in situ and trimmed by controlling the
anodisation voltage. Depending on the room temperature sheet resistance,
samples showed either superconducting or insulating behaviour at low
temperatures. A Coulomb blockade was observed for samples exceeding 6 kOhm per
square. Samples were also made in a single electron transistor-like geometry
with two weak links made by combined angular evaporation and anodisation. Their
current-voltage characteristics could be modulated by a voltage applied to an
overlapping gate.
