Preparation of nanostructured ultrathin silver layer

Silver is widely used for fabrication of plasmonic devices because of its unique optical constants. The nanostructure of the Ag layer is mainly influenced during the initial stage of the silver nucleation. Therefore, we focus our attention on studying this stage of silver growth. Nanostructured ultrathin silver layers are prepared by means of magnetron sputtering. The initial stage of the nucleation and the layer growth is studied by optical monitoring, which is based on spectrophotometric measurement of the sample reflectivity. The measured data are compared to a model of layered structure. The noncontinual (Volmer-Weber) mode of the layer nucleation is clearly distinguished in the monitored data. Thus, we are able to estimate the point of noncontinual layer coalescence. The optical data are correlated with in situ monitoring of the electrical resistance. We find that the nucleation mode and resulting nanostructure can be significantly influenced by an ultrathin silver oxide interlayer. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3562568]