Dewetting and nanopattern formation of thin Pt films on SiO2 induced by ion beam irradiation

Abstract

Dewetting and nanopattern formation of 3–10 nm Pt thin films upon ion irradiation is studied using scanning electron microscopy (SEM). Lateral feature size and the fraction of exposed surface area are extracted from SEM images and analyzed as functions of ion dose. The dewetting phenomenon has little temperature dependence for 3 nm Pt films irradiated by 800 keV ${\mathrm{Kr}}^{\mathrm{+}}$ at temperatures ranging from 80 to 823 K. At 893 K, the films dewet without irradiation, and no pattern formation is observed even after irradiation. The thickness of the Pt films, in the range 3–10 nm, influences the pattern formation, with the lateral feature size increasing approximately linearly with film thickness. The effect of different ion species and energies on the dewetting process is also investigated using 800 keV ${\mathrm{Kr}}^{\mathrm{+}}$ and ${\mathrm{Ar}}^{\mathrm{+}}$ irradiation and $\text{19.5\hspace{0.05em}}{\mathrm{keV\hspace{0.17em}He}}^{\mathrm{+}},$ ${\mathrm{Ar}}^{\mathrm{+}},$ ${\mathrm{Kr}}^{\mathrm{+}},$ and ${\mathrm{Xe}}^{\mathrm{+}}$ irradiation. The lateral feature size and exposed surface fraction scale with energy deposition density (J/cm²) for all conditions except $\text{19.5\hspace{0.05em}}{\mathrm{keV\hspace{0.17em}Xe}}^{\mathrm{+}}$ irradiation.