Ultratrace and microdistribution analysis in material sciences

Summary All-rounders and experts are two basic types of scientists. A harmonic cooperation between these two groups is essential for today's large study groups engaged in materials development. Materials development programmes in many high-tech countries are major fields of research supported by special financial arrangements (e.g. COST, EURAM or BRITE-programmes in Europe). Modern materials development is not possible without analytical guidance. This is not always realized by all engaged partners and it is a main obligation of analytical chemists to make aware of the role of a potent materials characterization in relevant development programmes. This should be demonstrated in two essential relevant areas: a) Bulk trace and ultra trace analysis of metals. Many important metal properties are directly or indirectly influenced by trace elements. In complex systems like fusion reactors or microelectronic components, trace contents of even minor metal parts might decisively influence system properties. As refractory metals and their silicides gain rising importance in VLSI microelectronic applications, their ultratrace characterization becomes a major challenge. Essential progress was possible by the complementary application of mass-spectrometric methods. Latest results and a critical survey will be given, including GDMS, SIMS, SSMS, IDMS and ICP-MS.Surprisingly, however, highest sensitivities and best detection limits were recently achieved by a combination of trace-matrix separation procedures and final end determination with ICP-MS. This combination also proved to be the most economic and safest approach from the view point of accuracy and precision. b) The analytical characterization of discontinuities and heterogeneities in solid matter. Practical examples are again taken from the study of refractory and hard metals and ceramics. A survey is given as to the manifold effects, heterogeneities and discontinuities exert on modern high-tech materials: as a function of their average diameter, they can either strengthen the material (dispersion strengthening), or they can cause deterioration of material properties e.g. as points of crack initiation, by grain boundary embrittlement etc. Together with most important methods for detection and characterization of heterogeneities and discontinuities, their evaluation and possible prevention during materials fabrication are discussed and pertinent examples are given. The phenomena of heterogeneous particles and pores are elucidated in more detail.

Acronyms used

1 Abbreviations for European research programmes AGATA Advanced Gas Turbines for Automobiles - BRITE Basic Research for Industrial Technologies for Europe - COST Cooperation in Science and Technology - EURAM European Research Activities Programme on Materials 2 Abbreviations in the field of refractory metals technology ADM Ammonium-Di-Molybdate - APT Ammonium-Para-Tungstate - HP High Purity - MHC Molybdenum-based alloy containing 1.2% Hf and 0.1% C - NS Non-sag (tungsten, used for lamp filaments and evaporative metallization techniques) - ODS Oxide Dispersion Strengthened - RM Refractory Metal - TZM Molybdenum-base alloy containing 0.5% Ti, 0.08% Zr and 0.025% C - UHP Ultra High Purity - VLSI Very large scale integration - ZHM Molybdenum-base alloy containing 0.40% Zr, 1.2% Hf and 0.15% C 3 Analytical technique names AA Activation Analysis - AAS Atomic Absorption Spectrophotometry - AES Auger Electron Spectrometry or Atomic Emission Spectrometry (only used in this work where it is clear that Auger Electron Spectrometry is not meant) - EDX(RS) Energy Dispersive X-Ray Spectrometry - EELS Electron Energy Loss Spectrometry - EP(X)MA Electron Probe X-Ray Microanalysis - GDMS Glow Discharge Mass Spectrometry - GFAAS Graphite Furnace Atomic Absorption Spectrometry - ICP-OES, MS Inductively Coupled Plasma — Optical Emission Spectrometry, Mass Spectrometry - ID-MS Isotope Dilution — Mass Spectrometry - LAS Classical photometry (Liquid Absorption — Spectrophotometry) - LEED Low Energy Electron Diffraction - MS Mass Spectrometry - NAA Neutron Activation Analysis - OES Optical Emission Spectrometry - SEM Scanning Electron Microscopy - SIMS Secondary Ion Mass Spectrometry - SSMS Spark Source Mass Spectrometry - TEM Transmission Electron Microscopy - TMS Trace-Matrix Separation (procedure) - WLD(-XRS) Wave Length Dispersive — XRS - XR(F)S X-Ray (Fluorescence) Spectrometry     

Trace-analytical methods for monitoring contaminations in semiconductor-grade Si manufacturing

Generating systematic data on incoming materials, processes, production environments and products by contamination monitoring and analyis is the key element of quality assurance in semiconductor fabrication. To be able to match the analytical capabilities to the requirements of improving materials and processes, the level of sophistication of contamination monitoring and analysis systems must be higher than the expected demands in the fabrication line. The accuracy of each analytical method has to be cross-checked by different independent techniques. Accuracy, precision, power of detection, analysis time and expenses should always be tailored to the particular case. All monitoring methods must run under statistical process control. The methods described meet the analytical requirements of the near future in semiconductor grade silicon manufacturing.Glossary AAS Atomic Absorption Spectrometry - ADD Acid-mixture Drop Decomposition of the native oxide and, occasionally of Si surface due to given acid etchant mixtures such as HF+HNO₃ in order to preconcentrate dissolvable metallic impurities of the surface (c.f. MAD, VPD, WSSD) - AEM Analytical Electron Microscopy - AEPS Auger Electron Appearance Potential Spectroscopy (=APAES) - AES Auger Electron Spectroscopy - AFM Atomic Force Microscope - AM Acoustic Microscopy - AMS Accelerator Mass Spectrometry (Tandem-SIMS) - APIMS Atmospheric Pressure Ionization Mass Spectroscopy - ARAES Angle-Resolved Auger Electron Spectroscopy - ARUPS Angle-Resolved Ultraviolet Photoemission Spectroscopy - ATR-FTIR Attenuated Total Reflection Fourier Transform Infrared Spectroscopy - BEEM Ballistic Electron Emission Microscopy - BMD heat induced Bulk Micro-Defects in monocrystalline Si after a specified thermal process cycle, corresponding to SIO_x precipitates in monocrystalline Si [31] - BSE Back Scattered Electrons - CE Capillary Electrophoresis (cf. CIA) - CIA Capillary Ion Analysis (cf. CE) - COP Crystal Originated Particle detected as LPD - CV Capacitance-Voltage measurement - CVD Chemical Vapor (phase) Deposit(ion) - CZ-Si monocrystalline Si grown by Czochralski-method from quartz crucible in a noble gas atmosphere - DCT Coulbe Crystal x-ray Topography - DLTS Deep Level Transient Spectroscopy [72] - DRAM Dynamic Random Access Memories operate as memory devices by storing charge near the Si wafer surface in micro-capacitors. Defects and impurities can cause the loss of the stored charge and a periodic refresh of the signals is required (cf. PTF). - DTDA Differential Thermal Desorption Analysis [73] - DZ Denuded Zone, i.e. a subsurface layer free of SiO_x precipitates - EBIC Electron Beam Induced Conductivity - EDS Energy Dispersive Spectroscopy - EDAX Energy Dispersive Analysis of X-rays - EELS Electron Energy Loss Spectroscopy - EG Extrinsic Gettering, i.e. removal of metals from the active device region by dislocation stress in the back side of the wafer - Elymat Electrolytical Metal Tracer [69] - EMP Electron MicroProbe - EPA Electron Probe Analysis - EPMA Electron Probe Micro-Analysis - ERDA Elastic Recoil Detection Analysis - ESCA Electron Spectroscopy for Chemical Analysis (= XPS) - ETV Electro Thermal Vaporization - fab manufacturing process or fabrication line of microchips - FESEM Field Emission Scanning Electron Microscopy - FIB Focused Ion Beam - FIM Field Ion Microscopy - FLAA FlameLess Atomic Absorption - FMEA Failure Mode and Effect Analysis - ()-FTIR (Microspot) Fourier Transform InfraRed Spectroscopy - FTPL Fourier Transform PhotoLuminescence - FZ-Si monocrystalline Si grown by float zone method from a polycrystalline Si rod in an rf-coil - GDMS Glow Discharge Mass Spectrometry - GFA Gas Fusion Analysis (heat extraction of O_i from Si by graphite reduction, [75]) - GF-AAS Graphite Furnace AAS - GLP Good Laboratory Practice (protocol defining general operations) - GMP Good Measurement Practice (protocol defining technique-specific operations) - GOI Gate Oxide Integrity test - Graff test surface precipitation of metallic silicide due to quenching annealed (1100°C) Si wafer, detection by Sirtl etch, cf. TEG haze test [76, 77] - HeD He thermal Desorption spectroscopy - HIBS Heavy Ion Backscattering Spectrometry - HREELS High-Resolution Electron Energy Loss Spectroscopy - HREM High Resolution Electron Microscopy index for interstitials (O_i, Si_i etc.) in monocrystalline Si - IC Ion Chromatography - ICISS Impact-Collision Ion-Scattering Spectroscopy - ICP-OES Inductively Coupled Plasma Optical Emission Spectrometry - ICP-MS Inductively Coupled Plasma Mass Spectrometry - IG Intrinsic Gettering, removal of metallic impurities from the device active region and trap them in the bulk using supersaturated O_i in Si and inducing SiO_x precipitation by thermal annealing - INNA Instrumental Neutron Activation Analysis [70, 71] - IR InfraRed Spectroscopy - IRAS Infrared Reflection Adsorption Spectroscopy - ISS Ion-Scattering Spectroscopy (cf. RBS) - LAMMA Laser (Ablation) Microprobe Mass Analyzer - LANG scanning Lang x-ray topography - LAR-RBS Lateral and Angle Resolved RBS-Imaging [78] - LEED Low Energy Electron Diffraction - LM-PC (non-contact) Laser/Microwave PhotoConductance - LOD Limit Of Detection (2–3 of noise level, [12]) - LOQ Limit Of Quantification (>6 of noise level, Fig. 2/3, [11, 13] - LPD Ligh Point Defect, sites scattering laser beam on monocrystalline Si surface (particles, pits, dimples, scratches, nm-terrasses, etc.) - LST Laser Scattering Topography - LT-FTIR Low Temperature Fourier Transform InfraRed Spectroscopy - LTV Local Thickness Variation - LPI-SNMS Laser Resonance Ionization SNMS - MAD Mixed Acid Droplet (cf. ADD, VPD, WSSD) - MAKYOH magic mirror optical surface reflection method (Jpn.) - Mb megabit, quantum of digital unit of information, number of memory addresses of a microchip, 4 Mb is about the information capacity of 250 pages/DIN A4 - ME Monochromatic Ellipsometry - MOR Modulated Optical Reflectance - MOS MetalOxide Semiconductor (transistor) - NRA Nuclear Reaction Analysis - NRIS NonResonant Ionization Spectroscopy - OF Orientation Flat to position Si wafers due crystal orientation - OM Optical Microscopy (usually differential interference/phase contrast Nomarski microscopy) - MOS-CAP/TAU Metal Oxide Semiconductor Capacitance/generation lifetime test for minority carrier - OSF hermal Oxidation-induced Stacking Fault in monocrystalline Si [31] - -PCD Microwawe reflection Photo Conductive Decay - PAM PhotoAcoustic Microscopy - PAS Positron Annihilation Spectroscopy - PCMS Plasma Chromatography Mass Spectroscopy - PC-SIMS Polyencapsulation Secondary Ion Mass Spectroscopy - PET Puddle Etch Test (HF/HNO₃-dissolution of 10 mm spots on as-sliced, as-lapped, as-etched wafers, [43]) - PFZ Precipitation Free Zone (cf. DZ) - PIXE Particle Induced X-ray Emission - PL PhotoLuminescence - POD Power Of Detection (LOD with real sample matrices, [14]) - 4-PP 4-Point Probe - PSI Phase Shift Interferometry - PSP Protocol for Specific Purposes (defining entire measurement program) - PTF Pause Time Failure can occur between periodic refresh of the stored data (cf. DRAM) - -Raman Raman Microprobe - RBS Rutherford BackScattering (cf. ISS) - RHEED Reflection High Energy Electron Diffraction - RIS Resonant Backscattering Ion Spectroscopy - SALI Surface Analysis by Laser Ionization - SAM Scanning Auger Microprobe/Microscopy - Schimmel etch defect/preferential etching for Si(100) [79] - Secco etch defect/preferential etching for Si(100) [79] - SEM Scanning Electron Microscopy - SERS Surface-Enhanced Raman Spectroscopy - SIMS Secondary Ion Mass Spectroscopy - SIRIS Sputter Initiated Resonant Ionization Spectroscopy - SIRM Scanning InfraRed Microscopy - Sirtl etch defect/preferential etching for Si(111) [79] - SOM-DPC Scanning Opt. Micr. Differential Phase Contrast - SNMS Sputtered Neutral Mass Spectroscopy - SOP Standard Operation Procedure (defining sampling and measurement process) - SPC Statistical Process Control - SPM Scanning Photon Microscope - SPV Surface Photo-Voltage - SRP Spreading Resistance Profiling - SSD Solid State Detector or Device - STM Scanning Tunneling Microscopy - S-ULSI Super-Ultra Scale Integration (Density)=16 Mb - SXES Soft X-ray Emission Spectroscopy - TCS Total Customer Satisfaction, the hotly pursued goal of all vendors of industrial goods - TDS Thermal Desorption Spectroscopy - TDBD Time Dependent Break-Down voltage - TDDB Time Dependent Dielectric Break-down voltage - TPD Temperature-Programmed Desorption - TEG haze test according to Telefunken Electronic Ges (cf. Graff-test) - TEM Transmission Electron Microscopy - TOF-SIMS Time of Flight Secondary Ion Mass Spectroscopy - TQM Total Quality Management - TTV Total Thickness Variation - TXRF Total Reflection X-Ray Fluorescence [80] - TREX Total Reflection Energy Dispersive X-ray fluorescence - ULSI Ultra-Large Scale Integration (Density)=4 Mb - UPS Ultraviolet Photoelectron Spectroscopy - US UltraSonic - VLSI Very Large Scale Integration (Density)=1 Mb - VPD Vapor Phase Decomposition (vapor phase reaction of HF with native Si-oxide and scanning the surface with a UPW or H₂O₂ solution droplet [38, 53], cf. ADD, MAD, WSSD) - Wright etch defect/preferential etching for Si(100) and Si(111) [79] - WSA Wafer Surface Analysis - WSSD Wafer Surface Scanner Device (automated VPD) - XPS X-ray Photoelectron Spectroscopy - XRD X-ray Diffraction - XRF X-ray Fluorescence - XRT X-ray Topography - XTEM X-ray Transmission Electron Microscopy     

Investigation of contemporary gilded forgeries of ancient coins

Four contemporary forgeries of ancient gold coins were investigated regarding techniques used for gilding, and the composition of the gold cover and the base metal core. The forged coins are a Daric of the Persian Empire, a Gold Stater in the name of Alexander, and two Solidi of the late Roman Empire. A combination of modern analytical methods such as Scanning Electron Microscopy (SEM), Electron Probe Micro Analysis (EPMA), X-Ray Fluorescence Spectrometry (XRF), and SecondaryIon Mass Spectrometry (SIMS) was used. The results demonstrate that the coins represent the main three technologies of gilding used in antiquity. The core of the Daric is a silver Siglos, plated by leaf gilding. The Gold Stater was forged by foil gilding using a silver core. The Roman Solidi have a core of either silver or copper and were plated by fire gilding. On account of our results it is possible to compare the forgers' profits made by use of the different technologies of forging.     

Volatile Compounds Present in Carbon Blacks Produced by Thermal Plasmas

Carbon black nanopowders were produced using two thermal plasma processes based on DC, respectively ICP plasma torches. Although the produced particles were in the nanometer size range, the values obtained for the surface area of the particles using a Brunauer Emmett Teller technique were very small. This indicated the presence of contaminants in the experimental powders, as confirmed by Raman spectroscopy and Thermogravimetric Analysis. A thermal treatment process was developed in order to extract these volatile compounds, which were then identified using a Gas Chromatography—Mass Spectrometry method. The experimental powders were analyzed using Scanning and Transmission Electron Microscopy, X-Ray Diffraction and Raman Spectroscopy before and after the thermal treatment in order to determine the effect of the heat treatment on the powder structural properties.     

Study and characterization of mural paintings from XIX Century in a noble Venetian (Italy) palace

The present paper describes the characterization carried out on the roof of a private palace located in the historical center of Venice (Italy). We focused our attention on the studies of original constituent materials (pigments and binders), in order to identify the pictorial technique of the artist and verify the stylistic attribution to Giuseppe Borsato, a Venetian painter operating between 18th and 19th century. Characterization of collected samples was carried on using both conventional and advanced analytical techniques, such as Optical Microscopy and Scanning Electron Microscopy coupled with Energy Dispersive X-Ray (SEM–EDS) microscopy, Fourier Transform Infrared Spectroscopy (FTIR) and High Performance Liquid Chromatography (HPLC) coupled with photodiode array detection (DAD) and Mass Spectrometry (MS). The finding of dating pigments (such as Cobalt blue and Cu–As based green) and of a complex binding's mixture compatible with the considered supposed period, allowed us to confirm the attribution hypothesis.     

Study and characterization of mural paintings from XIX Century in a noble Venetian (Italy) palace

The present paper describes the characterization carried out on the roof of a private palace located in the historical center of Venice (Italy). We focused our attention on the studies of original constituent materials (pigments and binders), in order to identify the pictorial technique of the artist and verify the stylistic attribution to Giuseppe Borsato, a Venetian painter operating between 18th and 19th century. Characterization of collected samples was carried on using both conventional and advanced analytical techniques, such as Optical Microscopy and Scanning Electron Microscopy coupled with Energy Dispersive X-Ray (SEM–EDS) microscopy, Fourier Transform Infrared Spectroscopy (FTIR) and High Performance Liquid Chromatography (HPLC) coupled with photodiode array detection (DAD) and Mass Spectrometry (MS). The finding of dating pigments (such as Cobalt blue and Cu–As based green) and of a complex binding's mixture compatible with the considered supposed period, allowed us to confirm the attribution hypothesis.     

Atomic fluorine in cobalt trifluoride thermolysis

The thermal decomposition of cobalt trifluoride was studied by High Temperature Mass Spectrometry (HTMS). It was ascertained that the rate of atomic fluorine evolution in the gas phase might be increased by adding small amounts of Ni(s) or CoF₂(s) to cobalt trifluoride. Scanning Electron Microscopy combined with Energy Dispersive X-ray spectroscopy (SEM/EDX) was used to determine the morphology and composition of the solid product surface layer formed under different rates of CoF₃(s) thermolysis.     

Concentration of elements in suspended matter discharges to Lerma River,Mexico

The S, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Zn and Pb concentration and the elemental composition of particles in suspended matter from principal discharges to Lerma River, have been evaluated. The elemental concentration in suspended matter has been obtained by Energy Dispersive X-Ray Fluorescence Spectrometry. The elemental composition of particles has been obtained by means of Energy Dispersive X-Ray Spectrometry (EDS). The results show that K, Ca, Ti, Mn and Fe are mainly from natural origin in the Upper Course of the Lerma River (UCLR), where the principal contributions probably come from dragging of soils and sediments in the rainy season and Cr, Cu, Zn and Pb are mainly from anthropogenic origin where the principal contributions come from urban and industrial untreated discharge. The application of Energy Dispersive X-Ray Spectrometry plus Scanning Electron Microscopy is useful in the characterization of suspended matter in natural, anthropogenic and mixed water discharges.     

Classical analysis including trace-matrix separation versus solid state mass spectrometry: A comparative study for the analysis of high purity Mo,W and Cr

The applicability of GDMS, SIMS, SSMS, NAA and TMS with AAS, ICP-OES and ICP-MS end determination for routine bulk ultratrace analysis of high purity refractory metals was investigated. Due to the heterogeneous distribution of trace elements in the sub-ppm range, sample consumption and analysis time have a tremendous influence on quantification with procedures of low sample consumption. As an example, GDMS, which is commonly used for ultrapure material certification by most of the manufacturers in Europe and the USA, exhibits discrepancies by more than one order of magnitude for repetitive analyses of a series of trace components in the same sample. Furthermore, results of different laboratories using the same instrument are frequently not comparable. Due to easy standardization and large sample consumption TMS procedures combined with FAAS, GFAAS, ICP-AES and ICP-MS as methods of end determination exhibit better precision and accuracy than GDMS and SIMS. Detection limits are comparably low or even better in case of ICP-MS end determination. TMS procedures are less expensive and less time consuming than highly sophisticated analytical techniques like GDMS, SIMS or NAA. Additionally, they can be easily applied by experienced personnel in a well equipped industrial analytical laboratory.List of Acronyms Used AAS Atomic Absorption Spectrometry - FAAS Flame Atomic Absorption Spectrometry - GDMB Gesellschaft Deutscher Metallhütten- und Bergleute - GDMS Glow Discharge Mass Spectrometry - GFAAS Graphite Furnace Atomic Absorption Spectrometry - ICP-AES Inductively Coupled Plasma Atomic Emission Spectrometry - ICP-MS Inductively Coupled Plasma Mass Spectrometry - IDMS Isotope Dilution Mass Spectrometry - NAA Neutron Activation Analysis - SIMS Secondary Ion Mass Spectrometry - SSMS Spark Source Mass Spectrometry - TMS Trace-Matrix Separation - VLSI Very Large Scale Integration - XRFS X-Ray fluorescence Spectroscopy Dedicated to Professor Günther Tölg on the occasion of his 60th birthday     

Synthesis, characterization and photocatalytic property of AgBr/BiPO4 heterojunction photocatalyst

A novel heterojunction AgBr/BiPO(4) photocatalyst was synthesized with the hydrothermal method. The photocatalyst was characterized by X-Ray powder Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectrscopy (XPS) and Diffuse Reflectance Spectroscopy (DRS). The XRD, SEM-EDS, TEM and XPS analyses indicated that the heterojunction structure formed during the process of hydrothermal treatment. The photocatalytic activity of the photocatalysts was evaluated by degradation of methylene blue dye (MB). The results indicated that the AgBr/BiPO(4) heterojunction exhibited a much higher photocatalytic activity than the pure BiPO(4). The mechanism of the enhancing AgBr/BiPO(4) heterojunction's photocatalytic activity was discussed. It was also found that the photocatalytic degradation of MB over AgBr/BiPO(4) heterojunction photocatalysts followed the pseudo-first-order reaction model.     

Investigation of Contemporary Forgeries of Ancient Silver Coins

Four ancient Roman silver coins from about 200 BC to 200 AD, mainly contemporary forgeries, were investigated in order to deduce the methods and materials used in the production of the forged coins. Special attention was devoted to a Denar from the Roman Republic, a C. Mamilius Limetanus denarius serratus (approx. 82 BC), because an original coin (pure silver) as well as a forgery were available. These coins both show serrated edges, i.e. notches all around with irregular spacing. A combination of microbeam analytical techniques was applied: Scanning Electron Microscopy (SEM), Electron Probe Micro Analysis (EPMA) and Secondary Ion Mass Spectrometry (SIMS). Some of the counterfeits consist of a base metal core plated with silver. The serrated Denar exhibits a plating layer with a thickness of approx. 100µm as determined by SEM and SIMS. This is an indication for foil silvering, as well as the apparent overlapping of the outer layer in one particular area.     

CuOx/TiO2光催化水蒸气还原CO2反应研究

以商品TiO2-P25为原料,通过浸渍法负载一定量过渡金属Cu,得到一系列不同含量的CuOx/TiO2光催化剂.利用X射线衍射(XRD),X-射线光电子能谱(XPS),BET,高分辨率透射镜(HRTEM),X射线荧光光谱(XRF)和光致发光光谱(PL)等方法对催化剂进行了详细表征,在自建的光催化反应器中评价了气态水光催化还原CO2反应的活性和CH4收率.结果表明负载CuOx后的TiO2纳米材料光催化性能显著提高,其中1%CuOx/TiO2样品紫外光照72 h后,CH4生成量达到了24.86μmol.gTi-1.同时,CuOx负载量、反应温度、反应时间等因素对CH4收率均有显著影响.     

Use of various spectroscopy techniques to investigate raw materials and define processes in the overpainting of Apulian red figured pottery (4th century BC) from southern Italy

Analytical investigations using Scanning Electron Microscopy (SEM), with Energy Dispersive Spectrometry (EDS), X-ray Diffraction (XRD), Infrared Spectroscopy (FT-IR) and High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (CP-MAS NMR), were carried out on white, yellow and red overpaintings on Apulian red-figured pottery fragments (4th century BC) from Altamura, Monte Sannace and Canosa - among the most relevant archaeological sites in ancient Peucetia - in order to outline technological features and define the nature of pigments. The results obtained allow us to highlight that Apulian objects have an external appearance which is very similar to Attic objects, but that they are nevertheless different, as they were made using locally available raw materials employing similar but not identical production technology. Perhaps familiarity, rather than real and proper continuity with the Attic pottery tradition, would explain the analytical results.Moreover, this paper proves that solid state nuclear magnetic spectroscopy (CP-MAS NMR) is a useful analytical tool for the examination of ancient pottery, which is also suitable for the identification of its firing temperature.     

SAM investigations of temperature programmed surface segregation of impurities in α-iron

The time development of the surface concentration of impurities such as sulphur and nitrogen in high-purity polycrystalline α-iron samples has been investigated by means of Auger Electron Spectroscopy (AES) and Scanning Auger Microscopy (SAM) during linearly increasing the temperature from about 100 to 850°C. The subsequent segregation of N and S revealed strong differences in the segregation kinetics of these elements — especially with respect to the contribution of the dominating transport mechanism (grain boundary diffusion and bulk diffusion). Calculating the effective diffusion coefficient of S from two subsequent segregation runs, strongly differing values were found. An interpretation of the change in the diffusion properties of sulphur is given based on SIMS (Secondary Ion Mass Spectroscopy) investigations performed before and after the thermal treatment.     

Influence of surface treatment on microstructure of stainless steels studied by Mössbauer spectrometry

Examination of surface microstructure of stainless steels is presented. Transmission Mössbauer spectrometry and Conversion Electron Mössbauer Spectrometry which provide information from the bulk and surface regions, respectively, were used. We concentrate on structural modifications that were caused by surface treatments including grinding, polishing, and electrolytic etching. Scanning Electron Microscopy with Energy Dispersive Spectrometry was adopted for visualization of surface differences. Formation of magnetic phases was revealed in the surface regions of X6CrNiTi1810 steel while no substantial effect of surface treatment was found in the ATABOR steel. Bulk regions in both steels are not affected by surface treatment.

     

Nano-structured nickel oxide based DNA biosensor for detection of visceral leishmaniasis (Kala-azar)

Sol-gel synthesized nickel oxide (NiO) film deposited onto indium tin oxide (ITO) coated glass plate has been utilized for the development of sensitive and stable DNA biosensor and demonstrated for diagnosis of visceral leishmaniasis also known as Kala-azar. Leishmania specific sensor is developed by immobilizing 23mer DNA sequence (oligonucleotide) identified from 18S rRNA gene sequences from Leishmania donovani. Characterization studies like X-Ray Diffraction and Scanning Electron Microscopy revealed the formation of nano-structured NiO, while immobilization of single strand (ss)-DNA of Leishmania was supported by UV-visible, Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy techniques. Response studies of ss-DNA/NiO/ITO bioelectrode are carried out using differential pulsed voltammetry in presence of methylene blue redox dye as a redox mediator. A linear response is obtained in the wide concentration range of 2 pg ml(-1) to 2 μg ml(-1) of complementary target genomic DNA (disease DNA) within the variation of 10% for 5 sets of studies. The observed results hold promise not only for diagnosis of Kala-azar patients but also hold enormous potential of the nano-NiO based probe for development of stable and sensitive biosensors.     

2-D analysis of Ge implanted SiO2 surfaces by laser-induced breakdown spectroscopy

2-D elemental distribution of Ge in silicon oxide substrates with differing implantation doses of between 3 × 10¹⁶ cm^− 2 and 1.5 × 10¹⁷ cm^− 2 has been investigated by Laser-Induced Breakdown Spectroscopy (LIBS). Spectral emission intensity has been optimized with respect to time, crater size, ablation depth and laser energy. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) coupled with Energy-Dispersive X-Ray Spectroscopy (EDX) have been utilized to obtain crater depth, morphology and elemental composition of the sample material, respectively. LIBS spectral data revealed the possibility of performing 2-D distribution analysis of Ge atoms in silicon oxide substrate. EDX analysis results confirmed that LIBS is capable to detect Ge atoms at concentrations lower than 0.2% (atomic). LIBS as a fast semi-quantitative analysis method with 50 µm lateral and 800 nm depth resolution has been evaluated. Results illustrate the potential use of LIBS for rapid, on-line assessment of the quality of advanced technology materials during the manufacturing process.     

Metallurgical applications of SIMS

Summary This paper reviews the unique advantages provided by Secondary Ion Mass Spectrometry (SIMS) for the characterization of heterogeneous conducting metallurgical samples: detection and imaging of the lateral distribution of every element (H-U), even at very low concentration and excellent depth resolution in the nanometer range. The advantages brought by coupling SIMS with other conventional microscopical and microanalytical techniques (SEM, EPMA, TEM/STEM) are illustrated by examples taken from the author's laboratory: quantitative analysis of the solid solution and within phases, surface, thin film and interface analysis by depth profiles. Special attention will be brought to the advantages of Ion Microscopy and the importance of high mass resolution. The difficulties associated with the variations of sputtering rate and ionization probability in multiphase systems will also be discussed.

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Anwendungen von SIMS in der Metallurgie

     

Characterization of the distribution of the sintering activator boron in powder metallurgical steels with SIMS

Powder metallurgy is a well-established method for manufacturing ferrous precision parts. A very important step is sintering, which can be strongly enhanced by the formation of a liquid phase during the sintering process. Boron activates this process by forming such a liquid phase at about 1200 °C. In this work, the sintering of Fe–B was performed under the protective atmospheres of hydrogen, argon or nitrogen. Using different grain sizes of the added ferroboron leads to different formations of pores and to the formation of secondary pores. The effect of boron was investigated by means of Secondary Ion Mass Spectrometry (SIMS) supported by Scanning Electron Microscopy (SEM) and Light Microscopy (LM). To verify the influence of the process parameters on the mechanical properties, the microstructure (pore shape) was examined and impact energy measurements were performed.The concentrations of B in different samples were varied from 0.03–0.6 weight percent (wt%). Higher boron concentrations are detectable by EPMA, whereas the distributions of boron in the samples with interesting overall concentration in the low wt% range are only detectable by means of SIMS.This work shows that the distribution of boron strongly depends on its concentration and the sintering atmosphere used. At low concentration (up to 0.1 wt%) there are boride precipitations; at higher concentration there is a eutectic iron–boron grain boundary network. There is a decrease of the impact energy observed that correlates with the amount of eutectic phase.     

Progresses in treatment of collagen and keratin-based materials with silver nanoparticles

The treatment of chromium tanned sheepskins with poly(hydroxyl urethane) and dispersion of chemically synthesized nanosilver showed the best resistance to fungi and bacterial exposure tests. These collagen-based materials containing different amounts of nanosilver were investigated by Atomic Absorption Spectroscopy, Atomic Force Microscopy and Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy. The influence of sheepskins treated with silver nanoparticles on the wound healing process was assessed and the nanoparticles concentration seems to have a positive effect up to 370 ppm and does not influence the inflammatory process above this concentration.