Premium
Ammonia Plasma Treatment of PTFE Under Known Plasma Conditions
Author(s) -
Pringle S. D.,
Joss V. S.,
Jones C.
Publication year - 1996
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/(sici)1096-9918(199611)24:12<821::aid-sia189>3.0.co;2-b
Subject(s) - ion , x ray photoelectron spectroscopy , chemistry , plasma , ammonia , langmuir probe , mass spectrometry , analytical chemistry (journal) , yield (engineering) , ionization , radical , nitrogen , inductively coupled plasma , plasma diagnostics , materials science , environmental chemistry , chromatography , chemical engineering , organic chemistry , physics , quantum mechanics , metallurgy , engineering
Ammonia plasmas produced in a helical resonator have been investigated using an energy‐selective mass spectrometer and an r.f.‐compensated Langmuir probe. The effect of processing parameters on the plasma composition and ion energy distributions have been examined. The dominant ion present in the plasma was found to be NH 4 + , which varied in concentration between 95% and 65%, dependent upon operating conditions. Similarly, by relatively small variations in processing parameters it was possible to vary the NH 3 + ion concentration between 1.7 and 31%. In addition, no radicals (NH 2 • , NH • or N • ) were detected using threshold ionization mass spectroscopy. Polytetrafluoroethylene (PTFE) samples were treated under a variety of different plasma conditions, and the chemical changes induced were studied by in situ XPS. Defluorination was observed to be greater under conditions that yield low ion energies or high concentrations of NH 3 + ions. Conditions giving rise to significant concentrations of NH 3 + ions result in the production of NH 3 + F ‐ groups. Evidence is provided suggesting that NH 3 + ions are much more reactive with PTFE surfaces than NH 4 + ions.