Structural analysis of organic ultrathin-layer by using Ar-gas-cluster ion beam sputter collecting method

Ar-gas-cluster ion beam (GCIB) sputter collecting method was developed and applied for multiple organic analysis methods of a polymer thin layer. By using this method, a polyvinylpyrrolidone thin layer (50 nm thick) on a polyethylene terephthalate substrate film could be selectively collected and analyzed by pyrolysis-gas chromatography-mass spectrometry. Furthermore, it was also applied to molecular weight distribution analyses of polymethylmethacrylate (PMMA) thin layers (50 nm thick) by matrix assisted laser desorption/ionization-mass spectrometry, and this revealed that the molecular weight of the collected PMMA polymer was slightly lower and showed a tendency that lowering of the molecular weight of collected PMMA decreased with an increase in the GCIB acceleration voltage. This phenomenon proposed that there were differences in damages between the first and second bombardments of Ar-GCIB sputtering processes, and the second bombardment area could be relatively larger than a low voltage, showing that the damage of the collected polymer was relatively less in high acceleration voltage of the GCIB.