Abstract
fastest growing surface analysis techniques. The formation of secondary ions from two ternary salts, [] and [], was studied using cluster-SIMs. Various primary ions at different energies and coincidence counting techniques were used to determine the influence of primary ion energy and complexity (number and kind of constituent ions) on secondary ion emission. [] was bombarded with [] and [] projectiles at constant energy (20 keV). The yield of [], a species non-representative of the sample, increased with respect to the yield of [] (a sample-representative species) as the member of atoms in the projectile increased. [] and [] projectiles were used at energies of 16 to 28 kev the When [] yield was more sensitive to the number of atoms in the primary ion than the yields of sample-representative species like [] and []. These results were indicative that the energy density deposited on the sample surface by a given projectile was the most important factor in the formation of species like [], which presumably arise from recombination/rearrangement reactions. [] was bombarded with [] at energies ranging from 10 to 20 kev. The yields of species non-representative of the sample, like [] and [], were more sensitive to the plumber of atoms in the projectile than the yields of sample-representative species like [] and []. These results indicated that the energy density deposited on the sample surface was the most important factor in the formation of non-representative species like [] which are produced by reduction reactions. This study demonstrated that the production of non-representative species from a sample increases when the energy density deposited on the sample surface was increased. The use of primary ions with many constituent atoms increases the energy density deposited on the surface with respect to projectiles with less constituent atoms at the same impact energy. The best polyatomic projectiles for analytical SIMS would therefore have few constituents if the production of artifact species is to be minimized.
Santiago, Vanessa (1998). A study of secondary ion formation from sodium salts using cluster-SIMS. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1998 -THESIS -S27.