Estimation of keV submicron ion beam width using a knife-edge method

A beam width measurement system has been developed for keV submicron ion beams of 0.1 mum or less in width assuming a round shape beam. The system enables to measure beam current change as a function of knife-edge position by cutting a beam focusing point (beam spot) with the sharp edge within a spatial resolution of 0.02 mum. The width of 30 keV order submicron H+ ion beam was estimated by fitting current change curves based on three different ion density models: uniform, flat-top and Gaussian. Among these models, the flat-top model provide the most reasonable beam width of 0.56 mum interpreting contribution of halo around the beam spot to beam width estimation. The beam width measurement system with the high spatial resolution and the data analysis based on the flat-top ion density model should contribute to accelerate developments of submicron ion beam production technologies. (C) 2003 Elsevier B.V. All rights reserved.