Abstract: Nanostructure deformation on 6H-SiC surface irradiated with highly-charged Xeq+(q=18, 26) ions to different fluences in two geometries of incidence by means of atomic force microscopy has been studied. The AFM measurement reveals that the irradiated surface is swelling. With increasing ion fluences, the step height between the irradiated and the unirradiated regions increases for Xe18+ irradiation. While for Xe26+ the step height firstly increases, and then decreases with increasing ion fluences. Moreover, the step height at normal incidence is higher than that at a tilted incident angle for the same ion and dose. These results can be attributed to the competition between the damage accumulation and the potential sputtering. A preliminary model including potential energy, incident angle, charge state and dose that accounts for the formation of observed nanostructures is proposed to discuss the underlying mechanism and to predict the step height. The paper concludes with suggestions for further research on the work and its potential applications.