Molecular depth profiling of polymers with very low energy ions

Houssiau, Laurent; Douhard, Bastien; Mine, N.

doi:10.1016/j.apsusc.2008.05.027

Cited by 46 publications

(39 citation statements)

References 10 publications

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“…Intact fragments of the polymer were preserved throughout the depth profile in the negative ion mode, whereas clusters combining those fragments with one or more Cs atoms, the so-called MCs n C clusters, were measured in the positive ion mode. This work was followed by other studies by the same authors on poly(ethylene terephthalate) (PET), [7] poly (methylmethacrylate) (PMMA) [7,8] and polystyrene (PS), [9] showing those polymers are amenable to molecular depth profiling using 250 eV Cs C ions. A first attempt to comprehend the Cs interaction with polymers is given in Ref.…”

Section: State-of-the Art In Low-energy Cs Polymer Depth Profilingmentioning

confidence: 95%

Molecular depth profiling with reactive ions, or why chemistry matters in sputtering

Houssiau¹,

Mine²

2011

Surface & Interface Analysis

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We have shown in recent papers that low-energy Cs + ions can be used successfully for molecular depth profiling of polymers. This paper reviews a few key experiments that provide a better understanding of the mechanisms involved in reactive ion depth profiling. It is shown that damaged polymer (polystyrene and polycarbonate) layers, initially bombarded with high-energy gallium irradiation, can be efficiently removed by low-energy Cs + sputtering so that the polymer molecular signal is restored. The role played by the primary ion energy is then studied by measuring the sputtering yields at different energies on polystyrene, poly (methylmethacrylate) and polycarbonate. Depth profiles on PC were also obtained at six different Cs + energies ranging from 150 to 1 keV. The best conditions were obtained at 200 and 250 eV, and the depth profile quality degrades above 500 eV. Finally, the negative ionization enhancement due to Cs implantation is studied by means of the Cs/Xe cosputtering method. All those experiments are consistent with a polymer cross-linking inhibition model, due to reactions between the implanted Cs atoms and the free radicals generated by ion irradiation. The main effect in molecular depth profiling with reactive ions is, therefore, a chemical effect.

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Section: State-of-the Art In Low-energy Cs Polymer Depth Profilingmentioning

confidence: 95%

Molecular depth profiling with reactive ions, or why chemistry matters in sputtering

Houssiau¹,

Mine²

2011

Surface & Interface Analysis

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“…Cs high reactivity ensures a negative ion signal enhancement, along with free radicals scavenging [18]. This source already proved its efficiency on both inorganics [19][20][21][22] and organics [23][24][25]. In this paper, we analyze model systems made of different metals (gold or chromium) and tyrosine multilayer systems deposited on silicon substrates.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Organic/Inorganic Materials Depth Profiling Using Low Energy Cesium Ions

Noël

Houssiau

2016

J. Am. Soc. Mass Spectrom.

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Abstract. The structures developed in organic electronics, such as organic light emitting diodes (OLEDs) or organic photovoltaics (OPVs) devices always involve hybrid interfaces, joining metal or oxide layers with organic layers. No satisfactory method to probe these hybrid interfaces physical chemistry currently exists. One promising way to analyze such interfaces is to use in situ ion beam etching, but this requires ion beams able to depth profile both inorganic and organic layers. Mono-or diatomic ion beams commonly used to depth profile inorganic materials usually perform badly on organics, while cluster ion beams perform excellently on organics but yield poor results when organics and inorganics are mixed. Conversely, low energy Cs + beams (<500 eV) allow organic and inorganic materials depth profiling with comparable erosion rates. This paper shows a successful depth profiling of a model hybrid system made of metallic (Au, Cr) and organic (tyrosine) layers, sputtered with 500 eV Cs + ions. Tyrosine layers capped with metallic overlayers are depth profiled easily, with high intensities for the characteristic molecular ions and other specific fragments. Metallic Au or Cr atoms are recoiled into the organic layer where they cause some damage near the hybrid interface as well as changes in the erosion rate. However, these recoil implanted metallic atoms do not appear to severely degrade the depth profile overall quality. This first successful hybrid depth profiling report opens new possibilities for the study of OLEDs, organic solar cells, or other hybrid devices.

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“…This effect is routinely used in SIMS depth profiling by applying oxygen sputtering to increase positive ion yields and cesium sputtering to increase negative ion yields [17,18]. In those cases, the secondary ion yields strongly increase with the concentration of the reactive species.…”

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confidence: 99%

Organic secondary ion mass spectrometry: Signal enhancement by water vapor injection

Mouhib

Delcorte

Poleunis

et al. 2010

J. Am. Soc. Mass Spectrom.

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The enhancement of the static secondary ion mass spectrometry (SIMS) signals resulting from the injection, closely to the sample surface, of H 2 O vapor at relatively high-pressure, was investigated for a set of organic materials. While the ion signals are generally improved with increasing H 2 O pressure upon 12 keV Ga ϩ bombardment, a specific enhancement of the protonated ion intensity is clearly demonstrated in each case. For instance, the presence of H 2 O vapor induces an enhancement by one order of magnitude of the [M ϩ H] ϩ static SIMS intensity for the antioxidant Irgafos 168 and a ϳ1.5-fold increase for polymers such as poly(vinyl pyrrolidone).

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Molecular depth profiling of polymers with very low energy ions

Cited by 46 publications

References 10 publications

Molecular depth profiling with reactive ions, or why chemistry matters in sputtering

Molecular depth profiling with reactive ions, or why chemistry matters in sputtering

Hybrid Organic/Inorganic Materials Depth Profiling Using Low Energy Cesium Ions

Organic secondary ion mass spectrometry: Signal enhancement by water vapor injection

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