In-situ SEM investigations on evolution of Sb fractal thin film under ion irradiation

Antimony (Sb) thin film was grown on Si(100) substrate by using molecular beam epitaxy (MBE) method, and during film growth, the substrate was maintained at room temperature. The morphology of the as-grown Sb film shows fractal morphology with a fractal dimension of 1.73, and it is due to the diffusion limited aggregation of fractal growth in Sb thin film on Si substrate. The evolution of fractal dimension of the thin film under 2 MeV Al + ion irradiation was investigated using our new in-situ ion irradiation and imaging with field emission scanning electron microscope ( i 4 - FESEM) facility. Upon ion irradiation, structural disorder has developed in the film, and the average fractal dimension has reduced significantly from 1.73 to 1.61, resulting in an increase in surface roughness. The contact angle measurements show the reduction in contact angle of the thin film which is consistent with in-situ observations. The observed change in fractal dimension is attributed to the evaporation of Sb atoms, which occurs during thermal spike regime of ion irradiation.