K. Piplits

Quantitative Analysis of Thin Aluminium-Oxynitride Films by EPMA

Abstract. Thin films of aluminium oxynitride with diverse composition were prepared by dc-magnetron sputtering of aluminium, utilising sputtering power as well as argon, oxygen and nitrogen gas flows to vary the composition. Since film properties depend mainly on the content of incorporated oxygen and nitrogen, a method for quantitative analysis of the main constituents based on electron probe micro analysis with energy dispersive detection was developed. The excellent precision of the quantitative results for aluminium as well as oxygen and nitrogen are shown. Furthermore, a film layer analysis program was applied for the quantification of several films deposited under the same deposition parameters on silicon wafers, from 520 nm down to 40 nm thickness, showing that electron probe micro analysis with energy dispersive detection is a reliable method for quantitative compositional analysis of thin aluminium oxynitride films down to approximately 20 nm thickness. Since this method of analysis provides only bulk information, expected inhomogeneities of the depth distribution of the film components were checked by secondary ion mass spectrometry depth profiles of two thin films and correlated to the EPMA results. The thickness of the films was determined by ellipsometry.

Surface analytical investigations of leached potash-lime-silica glass

SummaryThe layers formed on surfaces of leached silicate glass with potassium and calcium oxides were investigated by secondary ion mass spectrometry and nuclear reaction analysis. The results revealed a distinct influence of the corroding media on the leaching kinetics of the glasses. Details are discussed.

Characterization of carbon-boronnitride-coatings prepared with chemical vapor deposition by auger electron spectroscopy, electron probe microanalysis and secondary ion mass spectrometry

Abstract Several homogeneous carbon-boronitride (BCN) coatings were produced with cold-wall chemical vapor deposition varying the temperature of the deposition substrate from 800 °C up to 1400 °C. The deposition temperature has an influence on the growth rate as well as on the coating composition (C: 35–75 at%; B: 12–40 at%; N: 7–24 at%). Higher substrate temperatures lead to the formation of hemispheres (approximately 10 μm in diameter) on the surface, thus increasing the roughness of the BCN layers. Yet, all the hemispheres of one single sample are made up of the same composition. Furthermore, increasing substrate temperature leads to a rise in the carbon content whereas the ratio between boron and nitrogen is not affected by the substrate temperature, the B:N-ratio being 2:1.

SIMS investigation of MoS2 based sputtercoatings

Abstract Several multicomponent lubrication thin films consisting of TiAlN and molybdenum disulfide (MoS 2 ) were manufactured by magnetron cosputtering using different process parameters. The resulting thin films were analyzed by SIMS depth profiling, electron probe micro analysis (EPMA) and X-ray diffraction. EPMA measurements are used to determine the concentration of major elements of the thin film and to calculate relative sensitivity factors (RSFs) for SIMS quantification of the depth profiles. Whereas the concentration of titanium, aluminum and nitrogen nearly conforms the stoichiometric composition of TiAlN 2 , the concentration of molybdenum and sulfur are almost equal and do not comply the anticipated ratio of stoichiometric MoS 2 in all analyzed lubrication films. X-ray diffraction has been used to proof the amorphous nature of the film but also shows a significant difference in the crystalline structure between a pure TiAlN film and layers with cosputtered MoS 2 . While the TiAlN/MoS 2 cosputtered films are completely amorphous the TiAlN layer includes cubic TiN in an otherwise amorphous film. SIMS depth profiling indicates a constant amount of all analyzed elements through the film except sulfur which decreases from the surface to the bottom of the layer.

Brown spot corrosion on historic gold coins and medals

Abstract In 1998, in the Coin Cabinet of the Kunsthistorisches Museum, Vienna, Austria, brown spot corrosion was detected on about 400 gold coins and medals minted in Central Europe between the late 18th and early 20th century. The cause of the brown spots, their temporal and spatial frequency, the development of the corrosion and the most suitable restoration treatments and storage conditions for these objects has been and is still being studied. For the analysis of the historic coins and medals—as well as a set of test ducats produced in cooperation with the Austrian Mint—different analytical methods, i.e. light microscopy, scanning electron microscopy (SEM), measurement of polarisation curves, and secondary ion mass spectrometry (SIMS) were combined. From these investigations and the study of historical sources it could be shown that the brown spot corrosion is due to the inclusion of silver and/or silver/copper containing particles into the surface of the coins and medals. These inclusions are incorporated during the minting process. Afterwards they corrode to silver and copper sulphides owing to the presence of air pollution and objects releasing sulphur containing compounds (i.e. gypsum casts) nearby the historical objects.

SIMS: a capable method for BCN quantification

Abstract Obvious matrix effects often inhibit major component analysis carried out with secondary ion mass spectrometry (SIMS). Although MCs+ secondary ions (M represents the element to be analyzed) are used — already know as matrix independent for some compounds — feasibility of SIMS quantification has separately be validated for each new system. For the ternary system consisting of boron, carbon and nitrogen (BCN), all features possibly influences quantification, i.e. uniqueness of detected secondary ion signals, charge effects, altering measurement conditions, reproducibility or matrix effects are investigated and taken into account. The results indicate that an accurate quantification applying SIMS for major component analysis is possible for this system. Furthermore, deviations between SIMS results and real compositions are determined.

Comparison of depth profiles in SIMS by a fuzzy method

Automated quantitative comparison of depth-profiles recorded by SIMS based on a fuzzy difference measure has been used to characterize Sb and B implantation profiles in a marker experiment to study the diffusion of As in silicon. The variations of the concentration (intensity) measurements are described by a fuzzy set that is specified by smoothing the data with a polynomial digital filter. For each depth an individual spread as the size of variation is defined. Applications of the method enabled the influence of As-concentration and of annealing conditions on the implantation profiles of Sb and B to be quantified.

SIMS analysis of the oxidation behaviour of SiFeCr coated technical refractory metal alloys

Refractory metal alloys play an important role as highly thermostable materials in the air- and spacecraft industry. Due to their lack of oxidation stability at elevated temperatures it is necessary to protect them with coatings. The thermal-cycle-stability of Si20Cr20Fe-coatings on Nb10W2.5Zr and Ta10W was investigated by means of imaging Secondary Ion Mass Spectrometry; this showed the inward-diffusion of oxygen and other contaminants along cracks formed in the coating during thermal cycling and subsequent precipitation of oxides at the grain boundaries, leading to brittle fracture behaviour of the oxygen-affected surface zone. EDX measurements have been taken to determine the composition of the phases established in this complex system. SIMS Analyse des Oxidationsverhaltens von technischen Refraktarmetalllegierungen mit SiFeCr-Beschichtungen Refraktarmetall-Legierungen spielen eine wichtige Rolle als hoch temperaturfeste Werkstoffe in der Luft- und Raumfahrtindustrie. Wegen ihrer mangelnden Oxidationsbestandigkeit bei erhohten Temperaturen ist es erforderlich, sie durch Beschichtungen zu schutzen. Die Temperaturwechselbestandigkeit von Si20Cr20Fe-Beschichtungen auf Nb10W2.5Zr und Ta10W Legierungen wurde mittels Sekundarionen Massenspektroskopie untersucht. Dabei wurde gezeigt, das Sauerstoff und Verunreinigungen entlang von thermischen Rissen in das Material diffundieren und sich in Folge in einem oberflachennahen Bereich Oxide an den Korngrenzen bilden, die zu sprodem Bruchverhalten des betroffenen Bereichs fuhren. EDX Messungen wurden durchgefuhrt, um die quantitative Zusammensetzung der in diesem komplexen System gebildeten Phasen zu charakterisieren.