SURFACE-ROUGHNESS AND CONDUCTIVITY OF THIN AG FILMS

The diffuse scattering of conduction electrons at a rough surface has a considerable contribution to the resistivity of thin films, which is well known as the classical size effect. We have separated this contr ibution from other scattering mechanisms such as the phonon and bulk d efect scattering by the following procedure: Silver was deposited at l ow temperatures (almost-equal-to 130 K) onto a well-annealed relativel y thick silver base layer (almost-equal-to 24 nm), which has been depo sited onto a Si(111)-7 X 7 substrate. During deposition the resistivit y of the thin film was measured in situ, and afterwards the surface ro ughness was determined quantitatively with profile analysis of low-ene rgy electron diffraction. An increase of both resistivity and surface roughness was observed. Such an increase of the measured resistivity m ust be due to the increase of surface roughness because there was no c hange in temperature or concentration of bulk defects. With the measur ed surface roughness we are able to evaluate the additional resistivit y without any free parameters. The experiment reveals excellent agreem ent with the theoretical predictions.