The Experts below are selected from a list of 4431 Experts worldwide ranked by ideXlab platform
A. Bergmaier - One of the best experts on this subject based on the ideXlab platform.
-
elemental depth profiling of chlorinated polyamide based thin film composite membranes with Elastic Recoil Detection
Environmental Science & Technology, 2019Co-Authors: Rhea Verbeke, Günther Dollinger, A. Bergmaier, Stephan Eschbaumer, Veronica Gomez, Ivo F J VankelecomAbstract:The chlorine resistance of nanofiltration and reverse osmosis membranes is of high importance in the water treatment industry. Elastic Recoil Detection (ERD) is now presented as a powerful tool to uniquely provide elemental depth profiles, including hydrogen, of NaOCl-treated polyamide-based thin-film composite (TFC) membranes. The influence of pressure, pH, and chlorine feed concentration on the volume-averaged Cl uptake, the location of chlorine throughout the membrane, and the z-gradient in the Cl/N ratio is demonstrated. The results suggest that (i) higher volume-averaged Cl uptakes are achieved at higher chlorine doses and at acidic pH; (ii) chlorination is mostly restricted to the top layer; (iii) a gradient in the Cl/N ratio exists along the membrane depth; and (iv) the shape of this gradient is influenced by the chlorination pH and the applied pressure. Conclusions on the chlorination mechanisms could also be deduced. Conversely, no conclusive relationships between H fractions and Cl uptake could be drawn, even though changes in the H content after chlorination were observed. To corroborate these results and fully exploit the potential of ERD, the exact microstructure of the (chlorinated) TFC membranes should be better understood.
-
full elemental depth profiling with nanoscale resolution the potential of Elastic Recoil Detection erd in membrane science
Journal of Membrane Science, 2019Co-Authors: Rhea Verbeke, Günther Dollinger, A. Bergmaier, Stephan Eschbaumer, Hanne Marien, Ivo F J VankelecomAbstract:Abstract Extensive characterization is needed to understand how the physicochemical properties of polymeric membranes are related to their transport properties and to allow optimization of membrane design. Currently, most techniques characterize the (near)-surface region of the membrane, even though its bulk obviously also plays a significant role in the final membrane performance. To achieve depth-profiles of the elemental composition of both integrally skinned asymmetric (ISA) and thin-film composite (TFC) membranes, Elastic Recoil Detection (ERD), an ion beam analysis technique, is now introduced to the field as a potentially highly valuable tool to complement for instance XPS, EDX or RBS. The determination of the complete elemental composition, importantly also including hydrogen, as function of the membrane thickness allows to gain knowledge about its depth-heterogeneity at an impressive combination of ca. 15 nm resolution with ppm-range sensitivity. This very low Detection limit additionally allows the analytical quantification of e.g. remnants from synthesis conditions. The potential as well as the pitfalls of ERD as a novel, valuable technique for membrane characterization are critically discussed and illustrated by the determination of the thickness of polyamide-based top-layers of TFC membranes.
-
time of flight assisted δe e method for enhanced isotope separation capabilities in heavy ion Elastic Recoil Detection analysis
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2017Co-Authors: Stephan Eschbaumer, A. Bergmaier, D Seiler, G DollingerAbstract:Abstract The time of flight energy (TOF-E) setup installed at the scattering chamber of the Q3D magnetic spectrograph to perform heavy ion Elastic Recoil Detection (ERD) analysis at the 14 MV Munich Tandem Accelerator has recently been upgraded. Now, the energy detector of the TOF-E setup is additionally capable of performing Δ E - E measurements for high energy Recoil ions obtained from e.g. a 170 MeV 127 I projectile beam. Time of flight information is simultaneously acquired with the Δ E - E data for each detected ion. The combination of the TOF-E and the Δ E - E data gives the opportunity to set effective filter conditions to select for both, the elemental and the mass of the detected ion. As an example a boron doped carbon layer is analyzed and 10B and 11B is separated with the help of the combination of both methods.
-
the analysis of a thin sio2 si3n4 sio2 stack a comparative study of low energy heavy ion Elastic Recoil Detection high resolution rutherford backscattering and secondary ion mass spectrometry
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2006Co-Authors: Bert Brijs, Kaoru Nakajima, A. Bergmaier, Timo Sajavaara, Kai Arstila, Simone Giangrandi, Tom Janssens, Thierry Conard, K Kimura, G DollingerAbstract:Abstract The analysis of thin films in the range of 10 nm and less has become very important in microelectronics. The goal of this article is an evaluation of low-energy TOF-ERDA (time-of-flight Elastic Recoil Detection analysis) in comparison with low-energy SIMS (secondary ion mass spectrometry) and HRBS (high-resolution Rutherford backscattering spectrometry), using a thin SiO 2 /Si 3 N 4 /SiO 2 stack as a test vehicle. Comparisons are made on the depth resolution, its loss as a function of depth and the quantification accuracy.
-
high resolution Elastic Recoil Detection
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2004Co-Authors: G Dollinger, P. Neumaier, A. Bergmaier, L Goergens, Wilfried Vandervorst, Stefan JakschikAbstract:The quantitative analysis of light elements in ultra thin films being thinner than 10 nm is still a nontrivial task. This paper will summarise the prospects of high resolution Elastic Recoil Detection (ERD) using a Q3D magnetic spectrograph. It has been shown that subnanometer resolution can be achieved in ultra thin films and even monolayer resolution is possible close to the surface. ERD has best quantification possibilities compared to any other method. Sensitivity is sufficient to analyse main elements and impurities as e.g. being necessary for the characterisation of microelectronic materials. In addition, high resolution channeling ERD can be performed in order to get information on lattice location of light elements in crystalline ultra thin layers. The potential of high resolution ERD will be demonstrated by several applications where it is the most valuable tool for elemental profiling.
G Dollinger - One of the best experts on this subject based on the ideXlab platform.
-
time of flight assisted δe e method for enhanced isotope separation capabilities in heavy ion Elastic Recoil Detection analysis
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2017Co-Authors: Stephan Eschbaumer, A. Bergmaier, D Seiler, G DollingerAbstract:Abstract The time of flight energy (TOF-E) setup installed at the scattering chamber of the Q3D magnetic spectrograph to perform heavy ion Elastic Recoil Detection (ERD) analysis at the 14 MV Munich Tandem Accelerator has recently been upgraded. Now, the energy detector of the TOF-E setup is additionally capable of performing Δ E - E measurements for high energy Recoil ions obtained from e.g. a 170 MeV 127 I projectile beam. Time of flight information is simultaneously acquired with the Δ E - E data for each detected ion. The combination of the TOF-E and the Δ E - E data gives the opportunity to set effective filter conditions to select for both, the elemental and the mass of the detected ion. As an example a boron doped carbon layer is analyzed and 10B and 11B is separated with the help of the combination of both methods.
-
the analysis of a thin sio2 si3n4 sio2 stack a comparative study of low energy heavy ion Elastic Recoil Detection high resolution rutherford backscattering and secondary ion mass spectrometry
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2006Co-Authors: Bert Brijs, Kaoru Nakajima, A. Bergmaier, Timo Sajavaara, Kai Arstila, Simone Giangrandi, Tom Janssens, Thierry Conard, K Kimura, G DollingerAbstract:Abstract The analysis of thin films in the range of 10 nm and less has become very important in microelectronics. The goal of this article is an evaluation of low-energy TOF-ERDA (time-of-flight Elastic Recoil Detection analysis) in comparison with low-energy SIMS (secondary ion mass spectrometry) and HRBS (high-resolution Rutherford backscattering spectrometry), using a thin SiO 2 /Si 3 N 4 /SiO 2 stack as a test vehicle. Comparisons are made on the depth resolution, its loss as a function of depth and the quantification accuracy.
-
high resolution Elastic Recoil Detection
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2004Co-Authors: G Dollinger, P. Neumaier, A. Bergmaier, L Goergens, Wilfried Vandervorst, Stefan JakschikAbstract:The quantitative analysis of light elements in ultra thin films being thinner than 10 nm is still a nontrivial task. This paper will summarise the prospects of high resolution Elastic Recoil Detection (ERD) using a Q3D magnetic spectrograph. It has been shown that subnanometer resolution can be achieved in ultra thin films and even monolayer resolution is possible close to the surface. ERD has best quantification possibilities compared to any other method. Sensitivity is sufficient to analyse main elements and impurities as e.g. being necessary for the characterisation of microelectronic materials. In addition, high resolution channeling ERD can be performed in order to get information on lattice location of light elements in crystalline ultra thin layers. The potential of high resolution ERD will be demonstrated by several applications where it is the most valuable tool for elemental profiling.
-
depth profile analysis with monolayer resolution using Elastic Recoil Detection erd
EPL, 1998Co-Authors: G Dollinger, A. Bergmaier, C M Frey, T FaestermannAbstract:The conditions for obtaining optimum depth resolution in Elastic Recoil Detection (ERD) analysis of thin films using high-energy heavy ions are investigated. We estimate the principle limits given by energy straggling and small-angle scattering effects and show that monolayer depth resolution can be expected under optimized experimental conditions. Such a resolution is demonstrated in an ERD experiment for the first time by discrete signals of adjacent (002) graphite layers which is obtained using a 60 MeV 127I23+ ion beam and detecting 12C5+ Recoils with a magnetic spectrograph.
-
nonequilibrium charge states of Recoil ions in high resolution Elastic Recoil Detection analysis
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1998Co-Authors: G Dollinger, A. Bergmaier, Mourad Boulouednine, T FaestermannAbstract:Abstract The measured profiles of a high resolution Elastic Recoil Detection (ERD) analysis utilizing electrostatic or magnetic spectrographs may contain artefacts if only one charge state is measured. This effect is demonstrated by the analysis of 31.8 MeV 12 C q + Recoil ions of different charge states q + scattered from a pure graphite sample using 60 MeV 58 Ni 8+ ions at a scattering angle of 15° and by the analysis of a thin BN film. The primary charge state distribution obtained from scattering events very near the surface significantly deviates from the equilibrium one which is measured for carbon ions scattered deeper than 10 17 at/cm 2 below the surface. Charge exchange cross sections between the main charge states are obtained analysing the depth dependent charge state distributions.
Ivo F J Vankelecom - One of the best experts on this subject based on the ideXlab platform.
-
elemental depth profiling of chlorinated polyamide based thin film composite membranes with Elastic Recoil Detection
Environmental Science & Technology, 2019Co-Authors: Rhea Verbeke, Günther Dollinger, A. Bergmaier, Stephan Eschbaumer, Veronica Gomez, Ivo F J VankelecomAbstract:The chlorine resistance of nanofiltration and reverse osmosis membranes is of high importance in the water treatment industry. Elastic Recoil Detection (ERD) is now presented as a powerful tool to uniquely provide elemental depth profiles, including hydrogen, of NaOCl-treated polyamide-based thin-film composite (TFC) membranes. The influence of pressure, pH, and chlorine feed concentration on the volume-averaged Cl uptake, the location of chlorine throughout the membrane, and the z-gradient in the Cl/N ratio is demonstrated. The results suggest that (i) higher volume-averaged Cl uptakes are achieved at higher chlorine doses and at acidic pH; (ii) chlorination is mostly restricted to the top layer; (iii) a gradient in the Cl/N ratio exists along the membrane depth; and (iv) the shape of this gradient is influenced by the chlorination pH and the applied pressure. Conclusions on the chlorination mechanisms could also be deduced. Conversely, no conclusive relationships between H fractions and Cl uptake could be drawn, even though changes in the H content after chlorination were observed. To corroborate these results and fully exploit the potential of ERD, the exact microstructure of the (chlorinated) TFC membranes should be better understood.
-
full elemental depth profiling with nanoscale resolution the potential of Elastic Recoil Detection erd in membrane science
Journal of Membrane Science, 2019Co-Authors: Rhea Verbeke, Günther Dollinger, A. Bergmaier, Stephan Eschbaumer, Hanne Marien, Ivo F J VankelecomAbstract:Abstract Extensive characterization is needed to understand how the physicochemical properties of polymeric membranes are related to their transport properties and to allow optimization of membrane design. Currently, most techniques characterize the (near)-surface region of the membrane, even though its bulk obviously also plays a significant role in the final membrane performance. To achieve depth-profiles of the elemental composition of both integrally skinned asymmetric (ISA) and thin-film composite (TFC) membranes, Elastic Recoil Detection (ERD), an ion beam analysis technique, is now introduced to the field as a potentially highly valuable tool to complement for instance XPS, EDX or RBS. The determination of the complete elemental composition, importantly also including hydrogen, as function of the membrane thickness allows to gain knowledge about its depth-heterogeneity at an impressive combination of ca. 15 nm resolution with ppm-range sensitivity. This very low Detection limit additionally allows the analytical quantification of e.g. remnants from synthesis conditions. The potential as well as the pitfalls of ERD as a novel, valuable technique for membrane characterization are critically discussed and illustrated by the determination of the thickness of polyamide-based top-layers of TFC membranes.
H Timmers - One of the best experts on this subject based on the ideXlab platform.
-
nitrogen depletion of indium nitride films during Elastic Recoil Detection analysis
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2005Co-Authors: Santosh Shrestha, H Timmers, Scott K A Butcher, M Wintrebertfouquet, P P T ChenAbstract:Abstract Elastic Recoil Detection analysis of different types of indium nitride films has been performed using a 200 MeV Au beam. Recoil ions were detected with a gas ionisation detector featuring a large Detection solid angle. Severe and non-linear nitrogen depletion has been observed, with films grown by RF-sputtering losing nitrogen more quickly than MBE-grown films. Assuming the formation of molecular nitrogen as the decisive step leading to nitrogen loss, the nitrogen depletion process has been modelled using the bulk molecular recombination model. The model allows accurate extrapolations of the original nitrogen content of the material. Since the other important elements can also be quantified, the stoichiometry of the film can thus reliably be obtained from Elastic Recoil Detection analysis. All the films analysed have been found to have excess nitrogen.
-
round robin measurement of h implantation distributions in si by Elastic Recoil Detection
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2004Co-Authors: G Boudreault, Timo Sajavaara, H Timmers, R G Elliman, R Grotzschel, S C Gujrathi, C Jeynes, W N Lennard, E Rauhala, Y Q WangAbstract:Abstract A 200 mm amorphised Si wafer was implanted with 6-keV H + ions at a nominal fluence of 5 × 10 16 atoms/cm 2 . The uniformity of the implant was better than 2% over the wafer. Samples of the wafer were analysed for absolute H fluence by nuclear reaction analysis and Elastic Recoil Detection (ERD) analysis, including both helium and heavy ion beams, using various types of detector (Si with range foil, time of flight ERD, and a position-sensitive gas ionisation Δ E – E detector), various ion beams (He, Cl, Cu, I, Au) and independent analytical procedures. The results are compared and the inter-lab reproducibility is evaluated. The surface H, unstable under heavy ion beams, was resolved and accounted for throughout the analysis. Estimates of total combined uncertainties are about 6% for all participants, but the inter-lab reproducibility of the measurements was found to be 2.2%. Correct quantification of the H data from the gas ionisation detector is demonstrated. The uncertainty budget is discussed in detail.
-
accurate stoichiometric analysis of polycrystalline indium nitride films with Elastic Recoil Detection
Current Applied Physics, 2004Co-Authors: Santosh Shrestha, H Timmers, Scott K A Butcher, M WintrebertfouquetAbstract:Abstract Indium nitride thin films for potential application in high power, high frequency devices have been grown with reactive ion sputtering. Accurate film stoichiometries have been measured with Elastic Recoil Detection using 200 MeV Au projectile ions. The beam-induced depletion of nitrogen during analysis has been found to be severe and non-linear with ion fluence. Assuming the formation of molecular nitrogen as the decisive step leading to nitrogen loss, a model has been applied which reproduces the experimental data. The model allows accurate extrapolations of the original nitrogen content of the material. All films studied have been found to be nitrogen-rich and have large band gaps ranging from 2.14 to 2.3 eV. The amount of excess nitrogen correlates with the band gap energy suggesting a Moss–Burstein effect. The excess nitrogen may thus act as donor and account for the high charge carrier concentrations of up to 2 × 10 20 cm −3 . The magnitude of the nitrogen excess is consistent with a donor level 50 meV below the conduction band.
-
simplifying position sensitive gas ionization detectors for heavy ion Elastic Recoil Detection
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2000Co-Authors: T.r. Ophel, H Timmers, R G EllimanAbstract:Abstract Heavy ion Elastic Recoil Detection is an effective tool for materials analysis. This has been facilitated by the development of novel Detection systems, including large solid-angle gas-ionization detectors with position-sensitivity. With such detectors the exposure of the sample to the beam is reduced, however, data analysis can be complex. This paper reports on a detailed investigation of a detector design commonly used. The results of this work have led to suggestions for design-modifications, which considerably simplify detector operation and data analysis. The modifications have been implemented and tested. With the modified detector, the total energy information can be obtained by adding the signals from the anode electrodes, but also directly from a grid-electrode, obviating the need for the relative calibration of the anode electrodes. The subdivision of the energy loss electrode, together with a carefully chosen position of the entrance window to maintain optimum resolution for two ΔE signals, enable light and heavy ions to be resolved at the same gas pressure. The placement of a sawtooth electrode within the anode gives position information, which is linear and independent of atomic number and ion energy. Protons can be identified simultaneously with heavy ions by combining the information from the grid and residual energy signals, both amplified with high gain.
-
limitations to depth resolution in high energy heavy ion Elastic Recoil Detection analysis
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1998Co-Authors: R G Elliman, H Timmers, G R Palmer, T.r. OphelAbstract:Abstract The depth resolution of heavy-ion Elastic Recoil Detection analysis (HIERDA) was examinedfor Al and Co thin films ranging in thickness from 100 to 400 nm. Measurements were performed with 154 MeV Au ions as the incident beam, and Recoils were detected using a gas ionisation detector. Energy spectra were extracted for the Al and Co Recoils and the depth resolution determined as a function of film thickness from the width of the high- and low-energy edges. These results were compared with theoretical estimates calculated using the computer program DEPTH.
T Faestermann - One of the best experts on this subject based on the ideXlab platform.
-
depth profile analysis with monolayer resolution using Elastic Recoil Detection erd
EPL, 1998Co-Authors: G Dollinger, A. Bergmaier, C M Frey, T FaestermannAbstract:The conditions for obtaining optimum depth resolution in Elastic Recoil Detection (ERD) analysis of thin films using high-energy heavy ions are investigated. We estimate the principle limits given by energy straggling and small-angle scattering effects and show that monolayer depth resolution can be expected under optimized experimental conditions. Such a resolution is demonstrated in an ERD experiment for the first time by discrete signals of adjacent (002) graphite layers which is obtained using a 60 MeV 127I23+ ion beam and detecting 12C5+ Recoils with a magnetic spectrograph.
-
nonequilibrium charge states of Recoil ions in high resolution Elastic Recoil Detection analysis
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1998Co-Authors: G Dollinger, A. Bergmaier, Mourad Boulouednine, T FaestermannAbstract:Abstract The measured profiles of a high resolution Elastic Recoil Detection (ERD) analysis utilizing electrostatic or magnetic spectrographs may contain artefacts if only one charge state is measured. This effect is demonstrated by the analysis of 31.8 MeV 12 C q + Recoil ions of different charge states q + scattered from a pure graphite sample using 60 MeV 58 Ni 8+ ions at a scattering angle of 15° and by the analysis of a thin BN film. The primary charge state distribution obtained from scattering events very near the surface significantly deviates from the equilibrium one which is measured for carbon ions scattered deeper than 10 17 at/cm 2 below the surface. Charge exchange cross sections between the main charge states are obtained analysing the depth dependent charge state distributions.
-
Elastic Recoil Detection with single atomic layer depth resolution
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1998Co-Authors: G Dollinger, A. Bergmaier, C M Frey, T FaestermannAbstract:The necessary conditions for single atomic layer depth resolution in Elastic Recoil Detection (ERD) analysis will be summarized in this paper: First there are rigorous requirements for the ion beam conditions and for the energy resolution of the Recoil ion detector in order to obtain an energy resolution in the order of 5 × 10−4. Second, the most limiting factors in depth resolution are due to the physical limits imposed by small angle scattering effects and due to the energy loss spread of the incident and Recoil ions. Last but not least, the third point deals with irradiation damage which has to be carefully controlled in order to measure the original depth profile before it is altered by the ion beam. As studied by energy loss measurements in transmission geometry through thin carbon foils the energy spread of heavy ions strongly depends on the charge state of the incident ions. In order to obtain the smallest energy spread the data show that the charge state of the incident ions should be near equilibrium. Using a 60 MeV 127I23+ ion beam the resolution of single atomic carbon layers of a highly oriented pyrolythic graphite (HOPG) sample could be demonstrated analysing the 12C5+ Recoils with the Munich Q3D magnetic spectrograph. As far as we know it is the first time that separated signals of neighbouring atomic layers could be resolved using ERD.
-
limits in Elastic Recoil Detection analysis with heavy ions
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1996Co-Authors: G Dollinger, A. Bergmaier, Mourad Boulouednine, T Faestermann, C M FreyAbstract:Abstract Severe alterations of the sample by the ion beam limits the detectable concentrations in Elastic Recoil Detection analyses (ERDA). Therefore, sputtering and effusion yields were determined and an enhancement was found in comparison to collisional theory. The sputter yield ranges from 650 carbon atoms per incident 120 MeV 197 Au ion to about 2500 for hydrogen of a hydrogenated polycrystalline c-BN layer for 60 MeV 58 Ni ions, and up to several millions of CH x for organic materials using 60 MeV 127 I ions. In addition plural scattering and secondary reactions limit sensitivity, especially when probing materials which mainly contain light elements. The actual limits in ERD with respect to depth resolution and sensitivity are discussed in terms of these principle effects and those induced by the used Detection systems.
-
high resolution depth profile analysis by Elastic Recoil Detection with heavy ions
Analytical and Bioanalytical Chemistry, 1995Co-Authors: G Dollinger, A. Bergmaier, T Faestermann, C M FreyAbstract:Elastic Recoil Detection (ERD) with energetic heavy ions (e.g. 60–120 MeV127I) is a suitable method to measure depth profiles of light and medium heavy elements in thin films. The advantages of this method are reliable and quantitative results and elementally and isotopically resolved depth profiles. A relative energy resolution of 0.07% has been measured in real ERD-experiments using the Q3D magnetic spectrograph at the Munich tandem accelerator and a large solid angle of Detection of 5 msr. The good energy resolution allows atomic depth resolution near to the surface which has been obtained at flat and smooth carbon samples. A large solid angle of Detection is necessary to measure a depth profile with the desired accuracy before the sample is significantly altered by the ion beam. As an example carbon profiles of thin carbon layers, prepared by a laser plasma ablation deposition process, have been investigated revealing the high depth resolution and its power to resolve elemental profiles at gradiated interfaces.