Interest of silver and gold metallization for molecular SIMS and SIMS imaging

The metallization procedure, recently proposed for signal improvement in organic secondary ion mass spectrometry (metal assisted-SIMS or MetA-SIMS), has been quantitatively evaluated for Irganox 1010 and polystyrene fragment and quasimolecular ions. in addition to gold, we investigate the effect of silver evaporation as a sample treatment prior to static SIMS analysis. Ion yields and yield enhancement factors are compared for Ag and Au-metallized molecular films, pristine coatings on silicon and sub-monolayers of the same molecules adsorbed on silver and gold. The results are sample-dependent but, as an example, the yield enhancement calculated for metallized polymer additive (Irganox 1010) films with respect to untreated coatings is larger than two orders of magnitude for the quasimolecular ion and a factor between I and 10 for characteristic fragments. The interest of the method for imaging SIMS applications is illustrated by the study of a non-uniform coating of polystyrene oligomers on a 100 mum polypropylene film. (C) 2004 Elsevier B.V. All rights reserved.