  Highly reproducible Nb/Al(AlOx)/Nb Josephson junction based direct current
superconducting quantum interference devices (DC SQUID) were fabricated by
three dimensional etching using focused ion beam. Hysteretic and non-hysteretic
DC SQUID with critical current ranging from 25 to 1100 microampere were
fabricated by varying the Al barrier and oxygen exposure time. The fabricated
DC SQUIDs have shown periodic flux dependence with high modulation factor
reaching a value of 92% at 4.2 K.
