Importance of internal ion beam parameters on the self-organized pattern formation with low-energy broad beam ion sources

摘要

A first qualitative approach to the importance of the divergence angle and angular distribution of the ions within the broad beam (here called internal beam parameters) on the pattern formation by low-energy ion beam erosion is presented. Si (100) surfaces were irradiated with Kr~+, with an ion energy of 2 keV, using a Kaufman type broad beam ion source. It is found that the operating parameters of the broad beam ion source which are responsible for the angular distribution of the ions also affect the pattern formation. Especially, the effect of the acceleration voltage, discharge voltage, grid distance and operation time on the transition from ripple to dot pattern with increasing ion beam incidence angle were analyzed. The results represent additional evidence about the significance of the internal beam parameters and the need of the further investigation of their role on the pattern formation by low-energy erosion.