Secondary Ion Mass Spectrometry Data Research Articles

Secondary Ion Mass Spectral Imaging of Metals and Alloys.

Secondary Ion Mass Spectrometry (SIMS) is an outstanding technique for Mass Spectral Imaging (MSI) due to its notable advantages, including high sensitivity, selectivity, and high dynamic range. As a result, SIMS has been employed across many domains of science. In this review, we provide an in-depth overview of the fundamental principles underlying SIMS, followed by an account of the recent development of SIMS instruments. The review encompasses various applications of specific SIMS instruments, notably static SIMS with time-of-flight SIMS (ToF-SIMS) as a widely used platform and dynamic SIMS with Nano SIMS and large geometry SIMS as successful instruments. We particularly focus on SIMS utility in microanalysis and imaging of metals and alloys as materials of interest. Additionally, we discuss the challenges in big SIMS data analysis and give examples of machine leaning (ML) and Artificial Intelligence (AI) for effective MSI data analysis. Finally, we recommend the outlook of SIMS development. It is anticipated that in situ and operando SIMS has the potential to significantly enhance the investigation of metals and alloys by enabling real-time examinations of material surfaces and interfaces during dynamic transformations.

Understanding the Mechanism of Light-Induced Age-Related Decrease in Melanin Concentration in Retinal Pigment Epithelium Cells.

It is known that during the process of aging, there is a significant decrease in the number of melanosomes in the retinal pigment epithelium (RPE) cells in the human eye. Melanosomes act as screening pigments in RPE cells and are fundamentally important for protection against the free radicals generated by light. A loss or change in the quality of melanin in melanosomes can lead to the development of senile pathologies and aggravation in the development of various retinal diseases. We have previously shown that the interaction between melanin melanosomes and superoxide radicals results in oxidative degradation with the formation of water-soluble fluorescent products. In the present study, we show, using fluorescence analysis, HPLC, and mass spectrometry, that visible light irradiation on melanolipofuscin granules isolated from RPE cells in the human eye results in the formation of water-soluble fluorescent products from oxidative degradation of melanin, which was in contrast to lipofuscin granules and melanosomes irradiation. The formation of these products occurs as a result of the oxidative degradation of melanin by superoxide radicals, which are generated by the lipofuscin part of the melanolipofuscin granule. We identified these products both in the composition of melanolipofuscin granules irradiated with visible light and in the composition of melanosomes that were not irradiated but were, instead, oxidized by superoxide radicals. In the melanolipofuscin granules irradiated by visible light, ions that could be associated with melanin oxidative degradation products were identified by applying the principal component analysis of the time-of-flight secondary ion mass spectrometry (ToF-SIMS) data. Degradation of the intact melanosomes by visible light is also possible; however, this requires significantly higher irradiation intensities than for melanolipofuscin granules. It is concluded that the decrease in the concentration of melanin in RPE cells in the human eye with age is due to its oxidative degradation by reactive oxygen species generated by lipofuscin, as part of the melanolipofuscin granules, under the action of light.

Investigation of Interfacial and Interdiffusion Study of Ti2N MXene Phase from TiN/Ti multilayers

Ti2N MXene phase was synthesized by interdiffusion of TiN/Ti multilayers by dc-magnetron sputtering at 698 K. The Atomic force microscopy (AFM) reveals the root mean square (RMS) roughness of the TiN/Ti multilayer was ∼4.78 nm of pristine samples which increased to ∼5.74 nm after annealing. The total thickness of (TiN10 nm/Ti10 nm), (TiN5 nm/Ti5 nm), and (TiN2.5 nm/Ti2.5 nm) multilayers was 200 nm as estimated by X-ray reflectivity (XRR). The secondary ion mass spectroscopy (SIMS) data reveals the diffusivity of N2 in the (TiN/Ti) multilayer is ∼10−18 m2s−1 at 698 K. The X-ray diffraction (XRD) planes of (112), (200), (220), (224) are at 36.95⁰, 42.89⁰, 62.25⁰, and 78.53⁰ 2θ values respectively confirming the Ti2N MXene phase and the X-ray photoelectron spectroscopy (XPS) confirmed Ti(2p) and N(1s) core orbitals are at 457.14 eV and 397.17 eV on the surface of TiN/Ti multilayer thin films. The X-ray absorption spectroscopy (XAS) of N and Ti L-edges were found at 404.51 eV, and 462.38 eV respectively which were shifted towards the right and left respectively after annealing indicating an increase and decrease in the oxidation state. Raman bands TA, LA, and TO were shifted towards higher wave numbers to 238, 337, and 634 cm−1 respectively for annealed TiN/Ti multilayer thin films.

Surface modification of s235 steel, molybdenum, and tungsten using electron beam scanning and electric discharge machining

The process of surface modification of structural steel s235, molybdenum, and tungsten samples was carried out using two techniques—high-energy electron beam line scanning in a vacuum in a device used for electron beam welding and electric discharge machining (EDM), in which samples are submerged in the dielectric fluid. Elemental surface distributions were then examined using two spectrometric techniques: secondary ion mass spectrometry (SIMS) and glow discharge mass spectrometry (GDMS). Samples were also examined using scanning electron microscopy with energy dispersive x-ray analysis (EDX). SIMS, GDMS, and EDX data show the segregation of manganese out of the electron beam scan line at the surface of s235 steel. In the case of EDM machined s235 steel, no surface segregation of manganese is seen, while the line treated with this machining is enriched in hydrogen, carbon, and copper, as contaminants of the dielectric fluid (kerosene) and the copper electrode are used. The SIMS data for tungsten show that the electron beam cleans up the impurities, while the EDM technique adds them. The data for molybdenum show that the electron beam cleans the surface of hydrogen and iron while enriching it with sodium and potassium. EDM-treated molybdenum appears to be contaminated with carbon and potassium but detects lower levels of hydrogen, sodium, and copper than the untreated surface.

Effect of additive (Zr) and dopants (Pd & Sb) on the depth of migration of lighter lanthanides (Nd & Ce) from U-bearing metal alloys into T91 steel

The metal alloy fuel, which is considered as the advanced nuclear fuel, has its own limitations; namely, lower liquidus temperature, higher swelling, and is highly prone to breach the cladding due to fuel-cladding chemical interaction (FCCI). The mobile and insoluble fission products (FPs), especially lanthanide FPs are mainly responsible for FCCI. In the present study, the influence of additive (Zr) and dopants (Pd and Sb) on the depth of migration of two lanthanide FPs, namely Nd and Ce, from different uranium-bearing metal alloys into T91 (ferritic-martensitic steel) cladding material is investigated. Seven metal alloys, namely, U-Nd, U-Nd-Pd, U-Ce, U-Ce-Pd, U-Zr-Nd, U-Zr-Nd-Pd, and U-Zr-Nd-Sb, were prepared using arc melting technique. The amount of lanthanide FPs taken in the above alloys corresponds to about 10 at.% burn-up of a typical fast breeder reactor (FBR) fuel. The pulsed laser deposition (PLD) method was used to obtain alloys in the form of thin film on T91 cladding, with simultaneous in-situ annealing. Subsequently, these films were subjected to elemental depth profiling using secondary ion mass spectrometry (SIMS). The depth of migration for Nd and Ce from the seven metal alloy systems into T91 cladding was determined based on SIMS data. The extent of the individual and simultaneous effect of additive and dopant on the depth of migration was determined. Both dopants (Pd and Sb) are effective individually in binding Nd and Ce within the fuel matrix (in the U matrix) by forming stable inter-metallic compounds. The effect of Zr on the migration of lanthanide FPs is negligible in the presence of dopants. Stable inter-metallic phases responsible for binding lanthanides FPs are identified. A comparative study on the efficiency of two dopants (Pd and Sb) is also discussed. For the first time, the depth of migration of Nd and Ce from U metal alloys into T91 cladding was measured in the presence of dopants (Sb/Pd) by using a novel technique of PLD followed by SIMS. These studies are very useful for understanding FCCI.

Back to the basics of time-of-flight secondary ion mass spectrometry data analysis of bio-related samples. II. Data processing and display.

This is the second half of a two-part Tutorial on the basics of the time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of bio-related samples. Part I of this Tutorial series covers planning for a ToF-SIMS experiment, preparing and shipping samples, and collecting ToF-SIMS data. This Tutorial aims at helping the ToF-SIMS user to process, display, and interpret ToF-SIMS data. ToF-SIMS provides detailed chemical information about surfaces but comes with a steep learning. The purpose of this Tutorial is to provide the reader with a solid foundation in the ToF-SIMS data analysis.

Exploring the Relationship between Polymer Surface Chemistry and Bacterial Attachment Using ToF‐SIMS and Self‐Organizing maps

AbstractBiofilm formation is a major cause of hospital‐acquired infections. Research into biofilm‐resistant materials is therefore critical to reduce the frequency of these events. Polymer microarrays offer a high‐throughput approach to enable the efficient discovery of novel biofilm‐resistant polymers. Herein, bacterial attachment and surface chemistry are studied for a polymer microarray to improve the understanding of Pseudomonas aeruginosa biofilm formation on a diverse set of polymeric surfaces. The relationships between time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) data and biofilm formation are analyzed using linear multivariate analysis (partial least squares [PLS] regression) and a nonlinear self‐organizing map (SOM). The SOM models revealed several combinations of fragment ions that are positively or negatively associated with bacterial biofilm formation, which are not identified by PLS. With these insights, a second PLS model is calculated, in which interactions between key fragments (identified by the SOM) are explicitly considered. Inclusion of these terms improved the PLS model performance and shows that, without such terms, certain key fragment ions correlated with bacterial attachment may not be identified. The chemical insights provided by the combination of PLS regression and SOM will be useful for the design of materials that support negligible pathogen attachment.

Atomistic simulations for investigation of substrate effects on lipid in-source fragmentation in secondary ion mass spectrometry.

In beam-based ionization methods, the substrate plays an important role on the desorption mechanism of molecules from surfaces. Both the specific orientation that a molecule adopts at a surface and the strength of the molecule-surface interaction can greatly influence desorption processes, which in turn will affect the ion yield and the degree of in-source fragmentation of a molecule. In the beam-based method of secondary ion mass spectrometry (SIMS), in-source fragmentation can be significant and molecule specific due to the hard ionization method of using a primary ion beam for molecule desorption. To investigate the role of the substrate on orientation and in-source fragmentation, we have used atomistic simulations-molecular dynamics in combination with density functional theory calculations-to explore the desorption of a sphingolipid (palmitoylsphingomyelin) from a model surface (gold). We then compare SIMS data from this model system to our modeling findings. Using this approach, we found that the combined adsorption and binding energy of certain bonds associated with the headgroup fragments (C3H8N+, C5H12N+, C5H14NO+, and C5H15PNO4 +) was a good predictor for fragment intensities (as indicated by relative ion yields). This is the first example where atomistic simulations have been applied in beam-based ionization of lipids, and it presents a new approach to study biointerfacial lipid ordering effects on SIMS imaging.

Front-side and back-side secondary ion mass spectrometry analyses on advanced doping processes for ultra-large scale integrated circuit: A case study

The issues caused by the artifacts of sputtering/re-deposition and ion knock-in effects of the conventional front-side secondary ion mass spectrometry (SIMS) measurement are extensively investigated. Back-side SIMS measurement is used to confirm these hypotheses and resolve these issues. Based on back-side SIMS data, plasma immersion ion implantation (PIII) processed wafers show superior junction characteristics and less damages than beamline (BL)-based implant processed wafers, including shallower junction depth (58.9 nm vs. 64.2 nm), similar junction abruptness (9.0 nm/dec vs. 8.7 nm/dec), and less end-of-range defects. They are opposite to the misleading conclusions that front-side SIMS data provided. A better electrical performance by PIII processed device than that by BL-based implant processed device is demonstrated.

(Invited) Deep Level Defects in AlN Studied By UV-Visible Spectroscopy

The ultrawide-bandgap (UWBG) AlGaN alloy system is emerging as a promising material for next generation power semiconductor devices. The increase in bandgap as the alloy composition is varied from the binary endpoints GaN to AlN leads to an increase in the critical electric field, which is a key parameter determining the performance of power semiconductor devices. As development of GaN and SiC materials for high-frequency and high-power devices reaches a state of maturity, pursuit of improved device performance is generating interest in UWBG materials with larger bandgaps. High Al composition AlGaN alloys, in addition to offering increased critical electric fields, offer prospects for improved device performance in high temperature operation. Fundamental challenges to the development of AlGaN-based devices, such as controllable doping, electrical contacts, and effective passivation, remain, but a variety of power devices have already been demonstrated (1-3).Point defects strongly affect the material properties of semiconductors, with important consequences for device performance. In traditional semiconductors, such as Si, point defects have been studied extensively, and point defect engineering methods have been developed to enhance device performance. However, the properties of point defects in UWBG materials are not as well understood. Point defects may be introduced during device growth, fabrication, and operation. On the one hand, intentionally introduced impurities (dopants) are critical to the control of electrical transport, while on the other hand, unintentionally introduced impurities may act deleteriously as carrier traps or recombination centers. In AlGaN, compensation by deep level, native point defects or unintentionally incorporated impurities limits achievable free carrier concentrations in electronic devices, while defects and their complexes affect the optical properties in optoelectronic devices. Since point defects exert such a strong influence on material properties, and are often responsible for device degradation, knowledge of their formation mechanisms and material effects are essential to develop strategies for the required control of point defect concentrations (4).In this work, we studied the optical signatures of deep level defects in single crystal AlN substrates. AlN possesses a high thermal conductivity and a close lattice match to high Al composition alloys, which make it an excellent substrate choice for growth of AlGaN-based power electronic and optoelectronic devices. High-quality, 2-inch diameter AlN substrates with average threading dislocation densities below 103 cm-2 were recently demonstrated (5). However, high optical absorption in the ultraviolet-C (UV-C) region was observed in AlN substrates grown by physical vapor transport (PVT), due to a deep level absorption band related to the carbon impurity. This absorption band negatively impacts the efficiency of UV-C optoelectronic devices that require light propagation through the substrate. In order to reduce the unwanted UV-C absorption, we studied the optical properties of double-side polished, 2-inch, c-plane AlN substrates by ultraviolet-visible (UV-Vis) spectroscopy and developed strategies for point defect control. Spatially uniform absorption coefficients below 30 cm-1 at 265 nm were demonstrated across 2-inch substrates (6). In this talk, UV-Vis absorption, photoluminescence (PL) emission, and PL excitation spectra will be presented and correlated with measured impurity concentrations from secondary ion mass spectrometry (SIMS) data, in order to identify deep level defects in AlN. Finally, the mechanisms for reduction of UV-C absorption in PVT AlN will be discussed.References R. J. Kaplar, A. A. Allerman, A. M. Armstrong, M. H. Crawford, J. R. Dickerson, A. J. Fischer, A. G. Baca, and E. A. Douglas, ECS J. Sol. State Sci. and Technol. 6(2), Q3061 (2017).P. H. Carey IV, F. Ren, A. G. Baca, B. A. Klein, A. A. Allerman, A. M. Armstrong, E. A. Douglas, R. J. Kaplar, P. G. Kotula, and S. J. Pearton, IEEE Trans. Semicond. Manuf. 32(4), 473 (2019).A. G. Baca, A. M. Armstrong, B. A. Klein, A. A. Allerman, E. A. Douglas, and R. J. Kaplar, J. Vac. Sci. Technol. A 38, 20803 (2020).S. Washiyama, P. Reddy, B. Sarkar, M. H. Breckenridge, Q. Guo, P. Bagheri, A. Klump, R. Kirste, J. Tweedie, S. Mita, Z. Sitar, and R. Collazo, J. Appl. Phys. 127, 105702 (2020).R. Dalmau, J. Britt, H. Fang, B. Raghothamachar, M. Dudley, and R. Schlesser, Mater Sci. Forum 1004, 63 (2020).R. Dalmau, S. Kirby, J. Britt, and R. Schlesser, ECS Trans. 104(7), 49 (2021).

An algorithm for U–Pb geochronology by secondary ion mass spectrometry

Abstract. Secondary ion mass spectrometry (SIMS) is a widely used technique for in situ U–Pb geochronology of accessory minerals. Existing algorithms for SIMS data reduction and error propagation make a number of simplifying assumptions that degrade the precision and accuracy of the resulting U–Pb dates. This paper uses an entirely new approach to SIMS data processing that introduces the following improvements over previous algorithms. First, it treats SIMS measurements as compositional data using log-ratio statistics. This means that, unlike existing algorithms, (a) its isotopic ratio estimates are guaranteed to be strictly positive numbers, (b) identical results are obtained regardless of whether data are processed as normal ratios (e.g. 206Pb / 238U) or reciprocal ratios (e.g. 238U / 206Pb), and (c) its uncertainty estimates account for the positive skewness of measured isotopic ratio distributions. Second, the new algorithm accounts for the Poisson noise that characterises secondary electron multiplier (SEM) detectors. By fitting the SEM signals using the method of maximum likelihood, it naturally handles low-intensity ion beams, in which zero-count signals are common. Third, the new algorithm casts the data reduction process in a matrix format and thereby captures all sources of systematic uncertainty. These include significant inter-spot error correlations that arise from the Pb / U–UO(2) / U calibration curve. The new algorithm has been implemented in a new software package called simplex. The simplex package was written in R and can be used either online, offline, or from the command line. The programme can handle SIMS data from both Cameca and SHRIMP instruments.

Zoisite in cratonic eclogite xenoliths - Implications for water in the upper mantle

A significant portion of the Earth's water is found at trace levels in nominally anhydrous rock forming minerals in the crust and mantle. Its distribution has far-reaching implications in melt-generating processes, mantle rheology and the stability of the lithosphere. We report petrographic, major and trace element, Fourier transform infrared spectroscopy and secondary ion mass spectrometry data on four eclogite xenoliths from the Obnazhennaya kimberlite, Siberia that contain hydrous minerals at upper mantle conditions. Al-rich (>9.9 wt% Al2O3) omphacitic clinopyroxene, a major mineral of eclogites, contains crystallographically controlled exsolutions of CaO-rich (up to 23.6 wt%) garnet (coronae, lenses), garnet-zoisite (lamellae) or amphiboles (needle/blade-like exsolutions). The omphacite hosting the exsolved lamellae shows enrichment or depletion in major (Al, Si, Mg) and trace (e.g., HREE) elements compatible with garnet and zoisite, proportional to the abundance of exsolutions.We argue that zoisite likely formed concomitantly with garnet exsolution from a water- and Al-rich precursory omphacite, without any fluid addition. The compositional gradients are consistent with diffusion-controlled partitioning in a closed system, and their preservation indicates the exsolution likely took place shortly prior to eclogite entrapment by the kimberlite. Large, non-exsolved, omphacite grains contain minimum ~870–1500 ppm wt. H2O (determined as OH). We infer that intertwined lamellae of hydrous garnet (600–960 ppm wt. H2O) and minor (<1%) zoisite (2 wt% H2O) formed at mantle conditions due to progressive exsolution, without external fluids. Recalculated whole rock water contents range from ~320 to 970 ppm wt. H2O. These estimates exceed by far those for the surrounding peridotitic mantle and suggest that, although a minor component, eclogites may locally be an important water reservoir in the cratonic mantle.

Inter‐laboratory Characterisation of Apatite Reference Materials for Oxygen Isotope Analysis and Associated Methodological Considerations

Here we report on the oxygen isotope compositions of four proposed apatite reference materials (chlorapatite MGMH#133648 and fluorapatite specimens MGMH#128441A, MZ‐TH and ES‐MM). The samples were initially screened for 18O/16O homogeneity using secondary ion mass spectrometry (SIMS) followed by δ18O determinations in six gas source isotope ratio mass spectrometry laboratories (GS‐IRMS) using a variety of analytical protocols for determining either phosphate‐bonded or “bulk” oxygen compositions. We also report preliminary δ17O and Δ’17O data, major and trace element compositions collected using EPMA, as well as CO32− and OH− contents in the apatite structure assessed using thermogravimetric analysis and infrared spectroscopy. The repeatability of our SIMS measurements was better than ± 0.25 ‰ (1s) for all four materials that cover a wide range of 103δ18O values between +5.8 and +21.7. The GS‐IRMS results show, however, a significant offset of 103δ18O values between the “phosphate” and “bulk” analyses that could not be correlated with chemical characteristics of the studied samples. Therefore, we provide two sets of working values specific to these two classes of analytical methodologies as well as current working values for SIMS data calibration.

Molecular Formula Prediction for Chemical Filtering of 3D OrbiSIMS Datasets.

Modern mass spectrometry techniques produce a wealth of spectral data, and although this is an advantage in terms of the richness of the information available, the volume and complexity of data can prevent a thorough interpretation to reach useful conclusions. Application of molecular formula prediction (MFP) to produce annotated lists of ions that have been filtered by their elemental composition and considering structural double bond equivalence are widely used on high resolving power mass spectrometry datasets. However, this has not been applied to secondary ion mass spectrometry data. Here, we apply this data interpretation approach to 3D OrbiSIMS datasets, testing it for a series of increasingly complex samples. In an organic on inorganic sample, we successfully annotated the organic contaminant overlayer separately from the substrate. In a more challenging purely organic human serum sample we filtered out both proteins and lipids based on elemental compositions, 226 different lipids were identified and validated using existing databases, and we assigned amino acid sequences of abundant serum proteins including albumin, fibronectin, and transferrin. Finally, we tested the approach on depth profile data from layered carbonaceous engine deposits and annotated previously unidentified lubricating oil species. Application of an unsupervised machine learning method on filtered ions after performing MFP from this sample uniquely separated depth profiles of species, which were not observed when performing the method on the entire dataset. Overall, the chemical filtering approach using MFP has great potential in enabling full interpretation of complex 3D OrbiSIMS datasets from a plethora of material types.

Effect of poly(tert-butyl methacrylate) stereoregularity on polymer film interactions with peptides, proteins, and bacteria

The impact of polymer stereoregularity on its interactions with peptides, proteins and bacteria strains was studied for three stereoregular forms of poly(tert-butyl methacrylate) (PtBMA): isotactic (iso), atactic (at) and syndiotactic (syn) PtBMA. Principal component analysis of the time-of-flight secondary ion mass spectrometry data recorded for thin polymer films indicated a different orientation of ester groups, which in the case of iso-PtBMA are exposed away from the surface whereas for at-PtBMA and syn-PtBMA these are located deeper within the film. This arrangement of chemical groups modified the interactions of iso-PtBMA with biomolecules when compared to at-PtBMA and syn-PtBMA. For peptides, the affected interactions were explained by the preferential hydrogen bonding and electrostatic interaction between the exposed polar ester groups of iso-PtBMA and positively charged peptides. In turn, for protein adsorption no impact on the amount of adsorbed proteins was observed. However, the polymer stereoregularity influenced the orientation of immunoglobulin G and induced conformational changes in bovine serum albumin structure. Moreover, the impact of polymer stereoregularity occurred equally for their interactions with Gram-positive bacteria (S. aureus), which absorbed preferentially onto iso-PtBMA films as compared to two other stereoregularities.

Dominant hydrogen complex in natural anatase TiO2

A study combining vibrational spectroscopy and first-principles theory is presented for a hydrogen-related defect in natural anatase TiO2 that is characterized by an O–H vibrational mode at 3373 cm−1 (10 K). Based on complementary Raman scattering, IR absorption, electron paramagnetic resonance, and secondary ion mass spectrometry data supported also by ab initio calculations, it is tentatively proposed that the defect responsible for the 3373 cm−1 line includes two hydroxyl units located next to a substitutional iron atom, FeTiH2. The defect may exist in at least two charge states, whereby the 3373 cm−1 line is associated with the positive charge state of the complex.

Nano-Scale Depth Profiles of Electrical Properties of Phosphorus Doped Silicon for Ultra-Shallow Junction Evaluation

Electrical properties and microstructure of phosphorus (P) implanted p-type Si substrates were evaluated by four-point probe (4PP), Differential Hall Effect Metrology (DHEM), secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM) techniques, after RTA 750-950°C and CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser 120-140W annealing. When RTA temperature was increased, defect concentration at a-Si/c-Si interface gradually disappeared. For CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser annealing, defects were found to aggregate at the end of range (EOR) region. Sheet resistance (Rs) values decreased significantly with increasing RTA temperature due to defects disappearing at EOR. Rs did not change appreciably for the CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser annealing case. The dopant activation ratio was less than 50% below RTA temperature of 850 °C, and it increased to 70% at 950 °C. For CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser annealing, the activation ratio could reach to over 80% regardless of the laser power. The highest active concentration and the lowest resistivity or mobility were found to be within the top 20 nm region of the surface. Although RTA annealing conditions influenced dopant diffusion and the resulting electrical property depth profiles significantly, depth profiles did not change much with changes in CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser power level. It was demonstrated that DHEM data in conjunction with SIMS and TEM data can be successfully employed to evaluate, in detail, the electrical properties of ultra-shallow junctions for metal oxide semiconductor field effect transistor (MOSFET) applications.

Coupled hydrogen and fluorine incorporation in garnet: New constraints from FTIR, ERDA, SIMS, and EPMA

Abstract It is well known that some garnet compositions can incorporate hydrogen and/or fluorine at levels up to several wt%. However, accurate measurement of these elements can be difficult at trace to minor concentration levels, so they are frequently ignored in routine chemical analysis. Furthermore, the mechanisms of H incorporation are still under debate, and only one mechanism for F substitution is commonly considered. We employed infrared spectroscopy (FTIR), elastic recoil detection analysis (ERDA), secondary ion mass spectrometry (SIMS), and electron probe microanalysis (EPMA) to measure H and F concentrations and constrain incorporation mechanisms in ten grossular garnets. We also present SIMS data for 11 spessartine and two andradite garnets. Three grossular garnets were measured with ERDA to obtain an infrared integral molar absorption coefficient (εi) for H2O of 13 470 L/(mol·cm2). Grossular H2O and F concentrations range from 0.017 to 0.133 wt% and 0.012 to 0.248 wt%, respectively. Correlations between 16OH and 19F and interpretation of FTIR spectra prompt us to consider various coupled substitutions of H and F for Si, which can explain some high-frequency IR absorption bands that have been attributed previously to “hydrogrossular clusters” (variably sized clusters in which 4H substitute for Si) or to inclusions of hydrous minerals. A strong correlation between 16OH and 19F in spessartine and similar high-frequency IR bands implies a similar role for H-F substitution. Coupled H-F substitution is also probably relevant to some andradite-rich garnets, rare pyrope from the Dora Maira massif, and some synthetic garnets. Improvements in analytical methods for trace to minor H and F open up more possibilities for using these elements to calculate the activities of H2O and F-species in fluids that were in equilibrium with garnet-bearing phase assemblages, as well as constraining the recycling of these elements into the mantle via study of xenoliths.

Theoretical Analysis of Experimental Data of Sodium Diffusion in Oxidized Molybdenum Thin Films

In this work, the diffusion process of sodium (Na) in molybdenum (Mo) thin films while it was deposited on soda lime glass (SLG) was studied. A small amount of oxygen was present in the chamber while the direct-current (DC) magnetron sputtering was used for the deposition. The substrate temperatures were varied to observe its effect. Such molybdenum films, with or without oxidations, are often used in thin film solar cells, either as back contact or as hole transport layers. Secondary ion mass spectrometry (SIMS) was used to quantify the concentration of the species. A grain diffusion mechanistic model incorporating the effect of grain and grain boundary geometrical shape and size was developed. The model was used to provide an in-depth theoretical analysis of the sodium diffusion in molybdenum thin films that lead to the measured SIMS data. It was observed that not only diffusion coefficients should be considered when analyzing diffusion processes in thin films but also the ratio of grain boundary size to grain size. Both depend on substrate temperature and directly affect the amount of diffused species in the film. The data were analyzed under the light of the film growth speed versus diffusion front speed, the effect of oxygen content, and the effect of substrate temperature on the overall diffusion process. The temperature inversely affects the ratio of grain boundary size and grain size and directly affects the diffusion coefficient, which leads to a preferable temperature at which the highest amount of alkali can be found in the film.

A Methodology to Inter-Compare Brass and Such Alloys Manufactured at Different Geographical Locations

This paper is about a method developed to normalize the Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) data counts of each constituent ion in a mass spectra, by dividing each ion count with the total ion count. So by comparing their statistical means, data of different samples of any alloy like brass etc . from different places around the world can be inter-compared using TOF-SIMS data collected using similar separate instruments under similar experimental conditions. Such a methodology can also be extended to analysis of constituents of other materials using TOF-SIMS as well. Here, all brass samples were chosen on a representative global basis and had similar end uses. Variations in normalized mean counts of major constituent ions suggest that brass produced in different parts of the world for similar uses can be a little different in composition and can be readily identified and distinguished using their normalized statistical mean ion counts using TOF-SIMS. Their performance does not drastically change due to variation in such constituents of the alloy as the thermal treatments used on them were possibly different. Based on these observations, it was felt that unless there is a drastic change in any alloys’ micro-structure or crystalline phase properties, there will be no drastic change in its properties with variation of its’ major or minor alloying constituents. Data from literature using different aluminum alloys as a representative example and using their available data on micro-hardness and noting their variation with alloying also suggests such a phenomena