The damage formation by implantation of energetic (∼5 MeV) low Z ions (C, N, O, F) in LiNbO3 has been investigated. The surface damage growth as a function of the fluence is consistent with a mechanism of nucleation and 3D growth of fully disordered clusters. It is possible to describe this behaviour by considering two processes: the first one is the direct generation of nuclear damage whereas the second one is the partial conversion of the electronic excitation into atomic displacements, mediated by the local concentration of defects. Within this simple scenario the damage evolution has been described by an analytical formula. This formula suggested that the existence of pre-damage in the surface region can boost the damage growth. This was demonstrated by introducing nuclear damage in the first 0.6 μm surface layer by 500 keV O implantation followed by a subsequent 5 MeV O implantation. The final …