Characterization of a modular broad beam ion source

Abstract

We characterize the performance of a modular broad beam ion source by energy resolved mass spectrometry and beam profile measurements. Using the same source housing and grid system, we performed our experiments powering the source with a hot filament or an ECR excitation, respectively. In the ion energy distribution we detect various peak structures reflecting the potential profile across the ion source as well as different charge exchange and dissociation processes occurring in the beam. The position of these peaks on the energy scale allows conclusions to be formed about the original charge state of the ion, when produced by charge exchange, or on the original molecule, when produced by dissociation. The most important contribution to the ion beam is caused by process gas ions with important impurities from source materials appearing with reactive process gases. Using electronegative gases, a large amount of negative ions generated in the beam is observed.