Automatic matching of SAM, SIMS and EPMA images

Matching and analysis of dissimilar images of a given scene gathered from different sources are important processes for their integration (e. g. in the course of a multisource interpretation or quantification). However, prior to the analysis, geometric distortions caused by the acquisition process have to be eliminated. This problem involves two steps: the extraction of dominant image features (control structures), such as edges or regions with homogeneous elemental coverage and the estimation of the model parameters of the geometric transformation based on the calculated features. An approach for a 5-parameter automatic matching process for data from SAM (Scanning Auger Microscopy), SIMS (Secondary Ion Mass Spectroscopy) or EPMA (Eletron Probe Micron Analysis) multispectral images is presented. The parameters include global translation, rotation and scaling.     

Application of SIMS in semiconductor research

Summary Nowadays SIMS is a well-established analytical technique in semiconductor research. Materials research and process development are the main fields of application in silicon technology, whereas for III–V compound semiconductors much attention has been paid to assessment of multilayer structures grown by advanced growth methods. Recent applications of SIMS in these fields are the subject of the present paper. Emphasis will be placed upon optimizing the SIMS results with respect to accuracy and depth resolution.

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Anwendungen von SIMS in der Halbleiterforschung

     

The electron microanalyzer (EPMA): a powerful device for the microanalysis of filled polymeric materials

The electron probe microanalyzer is a device often used in the field of geology or in the glass and steel industries. However, it is barely known or used in the polymer field. Thus, in this paper, we investigate the use of electron probe microanalyzer for polymer microanalyses and compared it with a scanning electron microscope equipped with an energy dispersive spectrometer. To show the unique potential of this technique only develop in our lab for polymer application, three different samples were studied: (i) a fire protective epoxy‐based coating submitted to aging in salt water, (ii) the distribution of organometallic catalysts into a thermal isolative silicone polymer, and (iii) the fouling growth of milk protein (biopolymer) on a stainless steel surface. Compared to an energy dispersive spectrometer, with an electron probe microanalyzer it is possible to quickly create X‐ray mappings of low concentration elements at a good resolution, as well as allowing the interpretation of the mechanism of action for the three samples which was impossible using only an energy dispersive spectrometer because of its too low detection resolution. Copyright © 2015 John Wiley & Sons, Ltd.     

Application of EELS to the microanalysis of materials

Electron energy loss spectroscopy (EELS) is used in analytical electron microscopy (AEM) because it can provide results on the chemical composition and structure of a small volume of material. The practical application of EELS was demonstrated by the investigation of a refractory hard metal of the type WC-TiC-Co and by the investigation of a BaTiO₃ ceramic material. To demonstrate the present status of quantitative analysis by EELS, the spectra of Be₂SiO₄, TiB₂ and BaTiO₃ were quantified and the results indicate that quantitative analysis is feasible for major concentrations of light elements and also of heavier elements even in the presence of severe edge overlap.     

Fission Gas Bubbles Characterisation in Irradiated UO2 Fuel by SEM, EPMA and SIMS

The behaviour of gases produced by fission is of great importance for nuclear fuel operation. Within this context, an experimental method for the characterisation of the fission gas including gas bubbles in an irradiated UO₂ nuclear fuel was developed in our laboratory using SIMS, EPMA and SEM results. SIMS and EPMA have been used to measure the radial distribution of xenon and SEM gives information on bubble formation across the fuel pellet radius. Using SIMS, xenon concentration can be determined in the matrix and in the bubbles. A quantification method, allowing the determination of the total inventory of xenon, is proposed and qualified with EPMA results. It is concluded that the complementary micro-analytical techniques SIMS, EPMA and SEM are very powerful tools for the characterisation of the fission gas bubbles in irradiated nuclear fuel.     

Microanalysis of Hydrogen, Boron and Fluorine in Vesuvianite by Means of SIMS, EPMA and FTIR

Vesuvianite, a complex sorosilicate, often contains variable (from trace-to-minor-element) amounts of H, B and F. We describe a microanalytical study of H, B and F in vesuvianite by means of Electron Probe Microanalysis (EPMA), Secondary Ion Mass Spectrometry (SIMS), and single-crystal Fourier-Transform InfraRed (FTIR) spectroscopy. Most crystals investigated are B- (up to 3.67 wt% B₂O₃) and F-rich (up to 2.38 wt%); H₂O ranges from 0.243 to 0.665 wt%. The H data obtained by SIMS allowed us to calibrate the quantitative analysis of H₂O by FTIR spectroscopy. The resulting molar absorption coefficient (ɛ _i = 100 000 ± 2000 L · mol⁻¹ · cm⁻²) is in excellent agreement with working curves available from the literature. Moreover, the SIMS data allowed us to obtain the calibration curve to estimate the B₂O₃ content on the basis on the FTIR absorbance: a _i = 34000 ± 1400 · B₂O₃ (wt%).     

Quantitative analysis of W-C:H coatings by EPMA,RBS (ERD) and SIMS

Several analytical techniques have been used to characterize homogeneous films of tungsten-containing hydrogenated carbon (W-C: H), deposited on Si with a film thickness of 1–1.5 m. Electron probe microanalysis (EPMA) enables one to determine the major components W (3–43 at %) and C, impurities (< 2 at %) of Ar and O, and the mass thickness (300–1800 g/cm²) of the films. The agreement between the results of EPMA and the data (W-content, mass thickness) provided by Rutherford backscattering spectrometry (RBS) is 5–10% relative. Quantitative analysis of hydrogen in W-C:H films (1–16 at %) is carried out by the technique of elastic recoil detection (ERD). A suitable scheme for the determination of H in W-C: H films by SIMS is proposed, based on monitoring the intensity ratio of HCs⁺/CCs⁺ secondary ions.     

Distribution analysis of trace elements in low alloy steel by means of EPMA,SIMS, and TEM

A combination of chemical analysis, EPMA, SIMS, and TEM was applied to gain information on the bulk values, the microstructure and the microdistribution of contaminants. The limitations of classical chemical analysis were overcome by the application of highly sophisticated analytical techniques. Optimized measurement conditions were worked out for SIMS analysis and basic data such as relative sensitivity factors were gained for further investigations. A correlation between the microdistribution of contaminants and mechanical data could not be established so far, since only two samples were investigated.List of acronyms used BAS British Association of Standardisation (UK) - CGHE carrier gas hot extraction - DL detection limit - ED energy discrimination - EPMA electron probe micro analysis - E ₀ energy of primary ions - HMR high mass resolution - I _B primary ion beam current - NBS National Bureau of Standards (USA) - OES optical emission spectroscopy - PI primary ions - RSF relative sensitivity factor - SI secondary ions - SIMS secondary ion mass spectrometry - SKF SKF Analytica Taeby (Sweden) - TEM transmission electron microscopy - XRFA X-ray fluorescence analysis - d _A diameter of analyzed area     

Electron probe microanalysis (EPMA) measurement of thin-film thickness in the nanometre range

The thickness of thin films of platinum and nickel on fused silica and silicon substrates has been determined by EPMA using the commercial software STRATAGEM for calculation of film thickness. Film thickness ranged in the order 10 nm. An attempt was made to estimate the confidence range of the method by comparison with results from other methods of analysis. The data show that in addition to the uncertainty of the spectral intensity measurement and the complicated fitting routine, systematic deviation caused by the underlying model should be added. The scattering in the results from other methods does not enable specification of a range of uncertainty, but deviations from the real thickness are estimated to be less than 20%.     

Titanium distributions in zone melted materials measured by SIMS

Using a zone melting apparatus the influence of the different solidification processes on the Ti distribution has been investigated in model alloys and a technical steel. The concentration profiles after the conventional zone melting process have been measured using secondary ion mass spectrometry and were used for the determination of the distribution coefficients of Ti in pure Fe-Ti- and Fe-C-Ti-alloys. The registration of lateral elemental maps helps to identify and to eliminate measuring artefacts and allows the investigation of dendritic solidification structures.     

Titanium distributions in zone melted materials measured by SIMS

Using a zone melting apparatus the influence of the different solidification processes on the Ti distribution has been investigated in model alloys and a technical steel. The concentration profiles after the conventional zone melting process have been measured using secondary ion mass spectrometry and were used for the determination of the distribution coefficients of Ti in pure Fe-Ti- and Fe-C-Ti-alloys. The registration of lateral elemental maps helps to identify and to eliminate measuring artefacts and allows the investigation of dendritic solidification structures.     

Comparative Analysis of a Solar Control Coating on Glass by AES, EPMA, SNMS and SIMS

 A solar control coating was analysed by different methods of surface analysis with respect to the layer sequence and the composition and thickness of each sublayer. The methods used for depth profiling were Auger electron spectroscopy, electron probe microanalysis, secondary neutral mass spectroscopy and secondary ion mass spectroscopy based on MCs⁺. The structure of the coating was unknown at first. All methods found a system of two metallic Ag layers, embedded between dielectric SnO_X layers. Additionally, thin Ni-Cr layers of 1–2 nm were detected on top of the Ag layers. Thus the detected layer sequence is SnO_X/Ni-Cr/Ag/SnO_X/Ni-Cr/Ag/SnO_X/glass. The Ni:Cr ratio in the nm-thin layers could be quantified by every method, the Cr fraction corresponding to less than one monolayer. We compare the capabilities and limitations of each method in routinely investigating this solar control coating. Importance was attached to an effective investigation. Nevertheless, by combining all methods, measuring artefacts could be uncovered and a comprehensive characterisation of the system was obtained.     

Accurate Determination of Trace Amounts of Oxygen in CrAlN Hard Coatings by a Combination of WDS–EPMA and SIMS

Low amounts of oxygen in AlCrN hard coatings have been quantitatively analysed by means of WDS–EPMA. By combination with SIMS depth profiling, applying a calibration sample produced by ion implantation, the accuracy of the EPMA results was proven. Values as low as 0.07 at% were measured and the calculated detection limit is in the range of 0.01 at%.     

Investigation of various SiC materials by means of EPMA/WDS techniques

The microstructure and compositions of SiC materials from different sources and processing routes were investigated by means of EPMA/WDS and image analysis techniques. The influence of various sources of errors like carbon contamination and spectrometers defocusing on the analysis has been assessed.The presence of dissolved sintering aids, or impurities, and their distributions were investigated by EPMA/WDS. In addition, inhomogeneities, porosity agglomerations and heterogeneous inclusions were found in almost all the SiC materials, which are known to influence the corrosion and mechanical behavior of the material.Quantification of secondary phase contents was performed by means of image analysis, EPMA and, when possible, by density measurement. All methods are affected by errors of difficult assessment. In particular, the EPMA/WDS technique has to handle the problem of non homogeneous volumes of analysis. Two quantitative approaches were attempted, both based on the averaging of many points. In the first, the beam was highly focused. In the second approach, large areas (from 10 to 50 m in diameter) were illuminated. The errors and limits of these methods are discussed and the results compared.     

Quantitative analysis of silicon- and aluminium-oxynitride films with EPMA, SIMS, hf-SNMS, hf-GD-OES and FT-IR

A precise and economic way for quantitative bulk analysis of silicon/aluminium, oxygen and nitrogen in the technological important silicon- and aluminium oxynitride thin films based on FT-IR and EPMA is presented and the use of data gained by the latter method is discussed for the calculation of relative sensitivity factors for SIMS and hf-SNMS. Advantages and disadvantages of SIMS, hf-SNMS and hf-GD-OES were compared. The combination FT-IR/EPMA/SIMS offers at present the best possibility for a quantitative bulk and in-depth distribution analysis of such films in the range of 20 to 1000 nm thickness. Alternatively for thicker films, combinations of FT-IR/EPMA/hf-SNMS or FT-IR/EPMA/hf-GD-OES are easier to apply but their use is restricted to oxygen concentrations higher than 10 wt%.