Evaluation of secondary ion yield enhancement from polymer material by using TOF-SIMS equipped with a gold cluster ion source

We investigated the enhancement of the secondary ion intensity in the TOF-SIMS spectra obtained by Au+ and Au3 + bombardment in comparison with Ga+ excitation using polymer samples with different molecular weight distributions. Since the polymer samples used in this experiment have a wide molecular weight distribution, the advantages of the gold cluster primary ion source over monoatomic ion could accurately be evaluated. It was observed that the degree of fragmentation decreased by the usage of cluster primary ion beam compared with monoatomic ion beam, which was observed as a shift of the intensity distribution in the spectra. It was also found out that the mass effect of Au+ and Ga+ as monoatomic primary ion, resulted in about 10–60 times of enhancement for both samples with different molecular distributions. On the other hand, the Au3 + bombardment caused intensity enhancement about 100–2600 compared with Ga+ bombardment, depending on the mass range of the detected secondary ion species. The cluster primary ion effect of Au3 +, compared with Au+, therefore, was estimated to be about 10–45.