Low energy Ar+ ion beam induced kinetic roughening of thin Pt films on a Si substrate

Abstract A 30 nm Pt thin film evaporated onto a Si wafer was sputtered by 9.7 keV oblique Ar + bombardment at various ion fluences. The evolution of the modified sputtered films was monitored by atomic force microscopy (AFM) and high resolution scanning electron microscopy (HRSEM). The most interesting observation was the formation of mound-like structures on the metal surface. Morphological data were quantitatively analysed within the framework of the dynamic scaling theory. Analyses of the height–height correlation function for different ion fluences yield roughness exponents α in the range 0.65–0.87, while the root-mean-square roughness amplitude w evolves with the ion fluence φ as a power law w ∝ φ β , with the growth exponent, β =0.36. The results are discussed in terms of the existing continuum models developed for the ion sputtering process.