Fractal characterization of the silicon surfaces produced by ion beam irradiation of varying fluences

Si (1 0 0) is bombarded with 200 keV Ar+ ion beam at oblique incidence with fluences ranging from 3 × 1017 ions/cm2 to 3 × 1018 ions/cm2. The surface morphology of the irradiated surfaces is captured by the atomic force microscopy (AFM) for each ion fluence. The fractal analysis is performed on the AFM images. The autocorrelation function and height-height correlation function are used as fractal measures. It is found that the average roughness, interface width, lateral correlation length as well as roughness exponent increase with ions fluence. The analysis reveals the ripple pattern of the surfaces at higher fluences. The wavelength of the ripple surfaces is computed for each ion fluence.