Molecular weight dependence of molecular damage to polyethylene glycol (PEG) molecules by sputtering with Ar gas cluster ion beam

In secondary ion mass spectrometry (SIMS), the use of gas cluster ion beam (GCIB) as primary ions has enabled the measurements of organic materials in SIMS. However, the secondary ion yield in the high mass range remains low, and its improvement is required. In this article, we focused on molecular damage as a factor affecting secondary ion yield. To evaluate molecular damage by sputtering, Ar-GCIB was irradiated onto an organic polymer, and the sputtered particles were captured and analyzed by mass spectrometry. This method allows for the evaluation of molecular damage by analyzing changes in the molecular weight of the captured molecules. Consequently, it was confirmed that molecular damage caused by Ar-GCIB sputtering was observed in a polymer with a molecular weight of approximately 1500. Furthermore, it was suggested that molecular damage is more likely to occur as the molecular weight increases.