  We have used the two-step growth technique, quench condensing followed by an
anneal, to grow ultra thin films of silver on glass substrates. As has been
seen with semiconductor substrates this process produces a metastable
homogeneous covering of silver. By measuring the in situ resistance of the film
during growth we are able to see that the low temperature growth onto
substrates held at 100 Kelvin produces a precursor phase that is insulating
until the film has been annealed. The transformation of the precursor phase
into the final, metallic silver film occurs at a characteristic temperature
near 150K where the sample reconstructs. This reconstruction is accompanied by
a decrease in resistance of up to 10 orders of magnitude.
