Anomaly of film porosity dependence on deposition rate

This letter reports an anomaly of film porosity dependence on deposition rate during physical vapor deposition - the porosity increases as deposition rate decreases. Using glancing angle deposition of Cu on SiO ₂ substrate, the authors show that the Cu film consists of well separated nanorods when the deposition rate is 1 nm/s, and that the Cu films consists of a more uniform film when the deposition rate is 6 nm/s; all other deposition conditions remain the same. This anomaly is the result of interplay among substrate non-wetting, density of Cu nuclei on the substrate, and the minimum diameter of nanorods.