Ion-beam induced effects at 15 K in LiNbO3

In order to study the primary effects of the damage formation, LiNbO3z-cut crystals were irradiated at a temperature of 15 K. The irradiation was done with 30 keV H-, 50 keV Li-, 160 keV O- and 350 keV Ar-ions at ion fluences between 5×10115×1011 and 2×1017cm-2. To investigate the damage accumulation, Rutherford backscattering spectrometry (RBS) in channeling configuration was applied using 1.4 MeV He-ions without warming the sample. The RBS measurements were performed in steps of equal charges providing a series of subspectra. It was observed that the backscattering yield of the damaged region decreases with increasing number of subspectra indicating an annealing of defects as a consequence of the RBS-measurement. The energy deposited into electronic processes by the analyzing He beam is mostly responsible for the observed defect annealing. The amount of annealing depends on the defect concentration and was taken into account for the calculation of the undisturbed defect accumulation for the different ion species.