抄録
A size-selected Ar gas cluster ion beam (GCIB) was applied to secondary ion mass spectrometry (SIMS) of a polystyrene (PS) thin film, a 1,4-didodecylbenzene (DDB) thin film, and an ITO glass sample. Additionally, the samples were analyzed by SIMS using an atomic Ar+ ion projectile and X-ray photoelectron spectroscopy (XPS). All three samples were contaminated by poly(dimethylsiloxane) (PDMS) on the surface. Compared to the Ar+ SIMS spectra, the fragments in the PS and DDB SIMS spectra for Ar1550+, including siloxane, were enhanced more than ∼100-fold, while the hydrocarbon fragments were enhanced 10-20-fold. XPS spectra during beam irradiation indicate that Ar-GCIB sputters contaminants on the surface more effectively than the atomic Ar+ ion beam. These results indicate that a large gas cluster projectile can sputter a much shallower volume of organic material than small projectiles, resulting in an extremely surface-sensitive analysis of organic thin films. The shallow volume sputtering by GCIB is responsible for the preferential enhancement of the surface contaminants.
