A NOVEL MULTILAYER CIRCUIT PROCESS USING YBA2CU3OX SRTIO3 THIN-FILMS PATTERNED BY WET ETCHING AND ION MILLING/

A process combining hydrofluoric acid (HF) and Ar+ ion milling has bee n used to make YBa2Cu3Ox/SrTiO3/YBa2Cu3Ox(YBCO/STO/YBCO multilayer tes t circuits. Low-angle steps can be readily etched in STO and YBCO film s with this process. YBCO lines crossing 5 degrees steps have about th e same critical temperature T-c (89-99 K) and critical current density J(c) (>1x10(6) A/cm(2) at 86 K) as lines on planar surfaces. Via conn ections have the same T-c as other circuit components and adequate cri tical currents for most circuit designs. (C) 1996 American Institute o f Physics.