MEASUREMENT OF NEGATIVE-ION AND NEGATIVE-CLUSTER SPUTTERING WITH HIGHLY-CHARGED HEAVY-IONS

A single-detector technique for the measurement of negative ion time-o f-flight spectra is introduced in this work. Spectra are presented for 390 keV Xe44+ ions at normal incidence on different samples. Mass dis tributions for C-n and SinOm clusters indicate that highly charged ion s lead to a statistical off-surface formation of heavy clusters, where as low-energy singly-charged ions may directly produce heavy carbon cl usters. The detection technique has proven to be very efficient and mi ght even be used as a nearly non-destructive surface-analysis method f or investigations of time dependent surface modifications.