Thin monolayer and bilayer filsm of spin cast poly(methyl methacrylate) (PMMA), poly(2-hydroxyethyl methacrylate) (PHEMA), poly(lactic) acid (PLA) and PLA doped with several pharmaceuticals have been analyzed by dynamic SIMS using SF5+ polyatomic primary ion bombardment. Each of these systems exhibited minimal primary beam-induced degradation under cluster bombardment allowing molecular depth profiles to be obtained through the depth of the film. By combing secondary ion imaging with depth profiling, 3-dimensional molecular image depth profiles have been obtained from these systems. In another approach, bevel cross sections are cut in the samples with the SF5+ primary ion beam to produce a laterally magnified cross section of the sample that does not contain the beam-induced damage that would be induced by conventional ion beam FIB cross sectioning. The bevel surface can then be examined using cluster SIMS imaging or other appropriate microanalysis technique.
Citation: Applied Surface Science
Pub Type: Journals
beam-induced damage, cluster bombardment, depth profile, secondary ion mass spectrometry