Nucleation and growth studies of gold films prepared by evaporation and ion-assisted deposition

Abstract Thin gold films have been deposited onto glass substrates by electron-beam evaporation and by oxygen and argon ion-assisted deposition. The nucleation and growth of the films have been monitored in situ by ellipsometry and spectral reflectance and transmittance measurements. The composition of the film surface has been characterized by ion-scattering spectroscopy. These techniques show that the thickness at which coalescence of gold islands occurs is less for both ion-assisted films than for the evaporated film deposited on a clean substrate. Monitoring of coalesced films during sputter-etching combined with measurements of reflectance from both sides of the coated surface indicate that all films have a layer of density less than bulk near the air-film interface, and for evaporated and argon ion-assisted films, another near the gold-substrate interface. Oxygen ion-assisted films showed no evidence of an interfacial layer near the substrate and it is concluded that these films had a much greater area of contact with the substrate than evaporated or argon ion-assisted films.