The influence of the flooding gas during ToF-SIMS depth profiling was studied to reduce the matrix effect and improve the quality of the depth profiles. The profiles were measured on three multilayered samples prepared by PVD. They were composed of metal, metal oxide, and alloy layers. Dual-beam depth profiling was performed with 1 keV Cs⁺ and 1 keV O₂⁺ sputter beams and analyzed with a Bi⁺ primary beam. The novelty of this work was the application of H₂, C₂H₂, CO, and O₂ atmospheres during SIMS depth profiling. Negative cluster secondary ions, formed from sputtered metals/metal oxides and the flooding gases, were analyzed. A systematic comparison and evaluation of the ToF-SIMS depth profiles were performed regarding the matrix effect, ionization probability, chemical sensitivity, sputtering rate, and depth resolution. We found that depth profiling in the C₂H₂, CO, and O₂ atmospheres has some advantages over UHV depth profiling, but it still lacks some of the information needed for an unambiguous determination of multilayered structures. The ToF-SIMS depth profiles were significantly improved during H₂ flooding in terms of matrix-effect reduction. The structures of all the samples were clearly resolved while measuring the intensity of the M_nH_m^–, M_nO_m^–, M_nO_mH^–, and M_n^– cluster secondary ions. A further decrease in the matrix effect was obtained by normalization of the measured signals. The use of H₂ is proposed for the depth profiling of metal/metal oxide multilayers and alloys.

Unambiguous evidence is presented that the chloride ions play a dual role in the formation of a micrometre thick film of polymerized [Cu-Cl-MBI]_n. This occurs when the copper is exposed to 3 wt.% NaCl solution containing 1 mM of mixture of inhibitors 2-mercaptobenzimidazole, MBI, and octylphosphonic acid, OPA, in the molar ratio MBI:OPA of 9:1. The chloride ions act simultaneously as a promoter of polymerized [Cu–MBI]_n/[Cu–Cl–MBI]_nfilm formation and a reactant that is incorporated in the film, as confirmed by time-of-flight secondary ion mass spectrometry. Also, formation of a Cu₂O film under the Cu-inhibitor film was proven by focused ion beam microscopy, with chemical analysis being employed at the cross-section of the thick polymerized film. The Cu(I) oxide underlayer, together with the porous straw-like morphology of the [Cu–Cl–MBI]_noverlayer, is believed to be responsible for the excellent corrosion protection of copper, even in a chloride environment without the reservoir of MBI+OPA. We also report a new insight into the mechanism of degradation of the Cu–MBI/Cu–Cl–MBI film that results in the formation of (MBI)₂dimers. The inhibitor layer, formed in NaCl solution and containing the synergistic combination of MBI and OPA, showed outstanding resistance to degradation.

Defluorination of polytetrafluoroethylene (PTFE) surface film is a suitable technique for tailoring its surface properties. The influence of discharge parameters on the surface chemistry was investigated systematically using radio-frequency inductively coupled H₂ plasma sustained in the E- and H-modes at various powers, pressures and treatment times. The surface finish was probed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The measurements of water contact angles (WCA) showed increased wettability of the pristine PTFE; however, they did not reveal remarkable modification in the surface chemistry of the samples treated at various discharge parameters. By contrast, the combination of XPS and ToF-SIMS, however, revealed important differences in the surface chemistry between the E- and H-modes. A well-expressed minimum in the fluorine to carbon ratio F/C as low as 0.2 was observed at the treatment time as short as 1 s when plasma was in the H-mode. More gradual surface chemistry was observed when plasma was in the E-mode, and the minimal achievable F/C ratio was about 0.6. The results were explained by the synergistic effects of hydrogen atoms and vacuum ultraviolet radiation.

Fourier transform infrared spectroscopy (FTIR) is one of the most widely used vibrational diagnostic techniques to investigate gas-phase reactive oxygen and nitrogen species (RONS). However, the technique carries intrinsic challenges, particularly in relation to interfering peaks in the spectral data. This study explores the interfacial processes that occur when reactive oxygen and nitrogen species generated by a non-equilibrium air plasma interact with the metal halide windows of an FTIR gas cell, leading to the appearance and evolution of spurious absorption peaks which complicate spectral interpretation. Raman spectroscopy, X-ray photoelectron spectroscopy, time of flight secondary ion mass spectrometry and attenuated total reflectance-FTIR spectroscopy were used to elucidate the origin of spurious absorption peaks spanning the 1400–1300 cm⁻¹ spectral range as a result of KBr exposure to plasma generated species. It was found that plasma exposed KBr contained a lower atomic fraction of Br which was replaced by the NO₃ nitrate group, the main absorbance peak of which progressively evolved with plasma exposure and affected the window transparency over the corresponding FTIR region. A correlation was revealed between KNO₃ formation, plasma power and exposure time to a growth and change in molecular vibrational energies corresponding to asymmetric NO₃ stretching vibrations in the KNO₃ structure.