2018 Volume 61 Issue 7 Pages 435-439
Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) with low-energy bismuth cluster ion beam was investigated to achieve fragment-free ionization and high secondary ion yields of molecular ions. TOF-SIMS spectra taken by 2 keV Bi3＋ were compared with those taken by 54 keV Bi32＋. 2 keV Bi3＋ spectra showed much less fragmentation of organic molecules and there were few atomic secondary ions of such as 1H＋ and 12C＋. Moreover, secondary ions of intact molecules were clearly observed in 2 keV Bi3＋ spectra for some organic materials. Results suggest that low-energy bismuth primary ion beams are potential candidate for molecular ion detection in TOF-SIMS.