The inability to rapidly grow thick or multilayer epitaxial films for eithe
r electronic or electrical power applications limits the utility of fluorid
e-based processes for YBa2Cu3O7-delta (YBCO). This problem is due to the us
e of water vapor in the growth process, necessary for the dissociation of m
etallofluorides. Flowing wet gas at low temperatures is corrosive to cuprat
es and responsible for destroying underlying YBCO layers in attempts to gro
w secondary layers. This is avoided simply by increasing the temperature wh
ere vapor is introduced into the growth ambient. Resulting two-layer films
of YBCO have properties similar to those of high critical current density s
ingle-layer films.