Applied Physics A, Materials Science & Processing/ 6 p./ Received: 25 October 2006/Accepted: 15 November 2006We present a mechanical pressing technique for generating ultra-smooth surfaces on thin metal films by flattening the bumps, asperities, rough grains and spikes of a freshly vacuum deposited metal film. The method was implemented by varying the applied pressure from 100MPa to 600MPa on an e-beam evaporated silver film of thickness 1000 °A deposited on double-polished (100)-oriented silicon surfaces, resulting in a varying degree of film smoothness. The surface morphology
of the thin film was studied using atomic force microscopy.
Notably, at a pressure of ∼ 600MPa an initial silver surface with 13-nmRMS roughness was plastically deformed and transformed to an ultra-flat plane with better than 0.1 nm RMS. Our demonstration with the e-beam evaporated silver thin film exhibits the potential for applications in decreasing the scatteringinduced losses in optical metamaterials, plasmonic nanodevices and electrical shorts in molecular-scale electronic devices.
