Si ion implantation of SrTiO3 passivated YBa2Cu3O6+x films for multilayer processing of electronic circuits

Si ion implantation was used to inhibit superconductivity in YBa2Cu3O6+x th in films passivated with SrTiO3 (YBCO/STO) as a first Lithography step in t he fabrication of multilayer integrated circuits. Doses in the range of 1 X 10(15)/cm(2)-1 X 10(16)/cm(2) were found to be optimal for both effective inhibition of YBCO/STO films and enabling growth of an additional supercond ucting YBCO layer. In comparison to bi-layer YBCO/STO films, STO-only contr ol films were shown to be less susceptible to implant damage, which allowed higher quality growth of a second YBCO film. Besides vacancy and interstit ial creation, two additional types of implant damage mechanisms associated with the crystal chemistry of YBCO were identified - recrystallization and in-plane ferroelastic strain - both of which impeded the growth of addition al good-quality YBCO films. These two damage mechanisms were not observed i n implanted STO-only films. (C) 2000 Elsevier Science B.V. All rights reser ved.