Formation of Cobalt Nanoparticies by Thin Film Dewetting using Furnace and Pulse-Laser Annealing Processes

摘要

Co nanoparticies on silica substrates were fabricated by inducing a thin-film dewetting through two different processes-furnace annealing and pulsed-laser annealing. The effects of annealing temperature, film thickness and laser energy density on dewetting morphology and mechanism were investigated. Co thin-films with thicknesses between 3 to 15 nm were deposited using ion-beam sputtering, and then, in order to induce dewetting, thermally annealed in furnace at temperatures between 600 and 900 deg C. Some as-deposited films were irradiated using a Nd-YAG pulsed-laser of 266 nm wavelength to induce dewetting in liquid-state. Films annealed in furnace agglomerated to form nanoparticies above 700 deg C, and those average particle size and spacing were increased with an increase of film thickness. On the laser annealing process, above the energy density of 100 mJ/cm~2, metal films were completely dewetted and the agglomerated particles exhibited greater size uniformity than those on the furnace annealing process. A detailed dewetting mechanism underlaying both processes were discussed.