Metallic films are grown with a "spongelike" morphology in the as-deposited
condition using planar magnetron sputtering. The morphology of the deposit is characterized
by metallic continuity in three dimensions with continuous and open porosity on
the submicron scale. The stabilization of the spongelike morphology is found over
a limited range of the sputter deposition parameters, that is, of working gas pressure
and substrate temperature. This spongelike morphology is an extension of the features
as generally represented in the classic zone models of growth for physical vapor
deposits. Nickel coatings were deposited with working gas pressures up 4 Pa and
for substrate temperatures up to 1000 K. The morphology of the deposits is examined
in plan and in cross section views with scanning electron microscopy (SEM). The
parametric range of gas pressure and substrate temperature (relative to absolute
melt point) under which the spongelike metal deposits are produced appear universal
for other metals including gold, silver, and aluminum.
