Nanoscale pattern formation in Pt thin films due to ion-beam-induced dewetting

Atomic force microscopy is used to characterize the evolution of film morphology produced by heavy-ion bombardment. Pt films, 3 and 5 mn thick, are deposited on SiO₂ substrates and subsequently bombarded by 800 keV Kr⁺. Ion doses of >2 × 10¹⁴ initiate pattern formation and the dewetting of Pt films from the substrate. The film morphology becomes increasingly disconnected with increasing dose; at the highest doses, ( ∼2× 10¹⁶ cm^-2), isolated nanoparticles are formed with a uniform spacing. The results are explained by the nucleation of bare substrate patches and subsequent coarsening of the morphology by the molten zones created by individual Kr⁺ impacts.