COMPARATIVE AND COMPLEMENTARY PLASMA DESORPTION MASS-SPECTROMETRY SECONDARY ION MASS-SPECTROMETRY INVESTIGATIONS OF POLYMER MATERIALS

Thick layers of various polymer materials have been investigated by static secondary ion mass spectrometry (SIMS) and plasma desorption mass spectrometry (PDMS) with a new combination time-of-flight (TOF) SIMS/PDMS instrument. For all polymers investigated, characteristic spectra could be obtained with both desorption techniques. The yield (number of detected secondary ions divided by number of primary ions) of characteristic secondary ions for PDMS turned out to be 1-2 orders of magnitude higher than for SIMS. Oligomers of PEG (cationized with sodium), of PMTFMA (protonated), and in the negative spectra of PMMA (methylene splitting) have been desorbed from thick layers with both desorption techniques, but only the PDMS measurements show correct distributions. The sensitivity for surface contamination in SIMS is greater than in PDMS.