Study of the optical properties of nanometric palladium films grown on silicon substrates by electroless

The optical properties of nanometric palladium films deposited on Silicon (100) substrates were studied by multiple angle ellipsometry and AFM measurements. The meaning of the refractive index and film thickness measured on the noncontinuous Pd layers were interpreted through the effective medium theory. Palladium films were deposited by the electroless process by using an aqueous PdCl₂-HF electrolytic bath. The studied Pd films were selected with thicknesses under 50 nm to correlate their optical parameters with surface roughness due to incomplete covering of the silicon surface. The silicon surface conditions after the Pd deposition as well as the electrolytic bath composition determinates the optical characteristics of the films. The observed Pd particle distributions are discussed for two distinct variants of the deposition processes, and are compared to the case of a continuous Pd film.