Electronic sputtering of silicon suboxide films by swift heavy ions

Two regimes are discerned experimentally in the electronic sputtering of silicon suboxide (SiO(x)) films under irradiation with 50 MeV Cu ions. For x < 1 the removal rate is low and increases with x; for 1.5 < x < 2 the removal rate is high and about constant [(1.6-2.0)x10(3) atoms per incoming ion]. The transition occurs at x values where the electronic structure of SiO(x) has a transition. We propose a model, which connects the electronic sputter rate with the SiO(x) electronic structure considering the lifetime of the ion track.