N. Savvides et A. Katsaros, INSITU GROWTH OF EPITAXIAL YBA2CU3O7 THIN-FILMS BY ON-AXIS UNBALANCEDDC MAGNETRON SPUTTERING, Thin solid films, 228(1-2), 1993, pp. 182-185
In-situ superconducting YBa2Cu3O7 thin films are grown epitaxially ont
o MgO(100) substrates by on-axis d.c. magnetron sputtering. The magnet
ron uses an unbalanced magnetic field configuration to circumvent resp
uttering effects, and high quality thin films are realized with excell
ent reproducibility. A stoichiometric target is sputtered in an Ar-O2
mixture (Ar-to-O2 ratio of 15 to 1) and films are deposited onto the h
eated substrates placed 40 mm directly in front of the target. We repo
rt on the growth and properties of films prepared as a function of spu
ttering pressure p(t) = 1 - 100 Pa, and as a function of the heater te
mperature T(s) = 600-860-degrees-C. c axis epitaxy is obtained over a
wide range of deposition conditions (T(s) greater-than-or-equal-to 700
-degrees-C; p(t) greater-than-or-equal-to 30 Pa). Typical films have e
xcellent crystalline quality, a transition temperature T(c) = 85-90 K,
a critical current density J(c)77 K greater-than-or-equal-to 10(6) A
cm-2 and a resistance ratio R300 K/R100 K = 2.0-3.1.