Recent success in the development of scanning force microscopy has initiated significant progress in the study of surface modifications on an atomic scale induced by single swift ion impact. As it has been shown recently, large amounts of energy deposited due to severe electronic excitation in the wake of high-energy heavy ions can generate remarkable changes in the surface topography in a variety of materials. Among materials where surface effects of dense ionization are less studied are the radiation-resistant ceramics and oxide crystals, like Al2O3 and MgO, having a relatively high threshold of specific ionizing energy loss for structural disorder enhancement. Because these insulators are considered as candidates for inert matrix fuel hosts for fission reactors, high-energy heavy ion irradiation simulating a fission product’s impact is of considerable practical interest due to the large number of fission track recoils in reactor fuel.   In this report we present and discuss the results of complementary atomic force microscopy and high resolution transmission electron microscopy examination of hillock morphology on surface of single crystalline Al2O3 irradiated with swift (E >1 MeV/amu) Kr, Xe and Bi ions. It was found that hillocks are crystalline in nature. At the same time the hillocks overlapping may trigger amorphization process in irradiating material.