Very large scale integration of nanopatterned YBa2Cu3O7-delta Josephson junctions in a two-dimensional array.

Very large scale integration of Josephson junctions in a two-dimensional series-parallel array has been achieved by ion irradiating a YBa(2)Cu(3)O(7-delta) film through slits in a nanofabricated mask created with electron beam lithography and reactive ion etching. The mask consisted of 15820 high aspect ratio (20:1), 35 nm wide slits that restricted the irradiation in the film below to form Josephson junctions. Characterizing each parallel segment k, containing 28 junctions, with a single critical current I(ck) we found a standard deviation in I(ck) of about 16%.