In‐situ Messung dünner Schichten auf Architekturglas

For the deposition of modern coatings on architectural glass (energy‐saving, solar control, anti‐reflective), reactive magnetron sputtering plays an outstanding role. The production of these coatings by reactive sputtering requires a manufactoring equipment, that ensures high quality as well as efficient deposition of the coatings. Thin film measurement by in‐situ ellipsometry can very impressively used for monitoring and controlling the film properties, in particular in the case of more complex coatings. With regard to long‐term stability the in‐situ film measurement is of special importance with respect to the use of the novel mid‐frequency magnetron sputter technique. This technique allows the deposition rate to be increased up to 500 %, however, a dynamical plasma stabilization in the so called »transition mode« is necessary. Within the framework of a project supported by the BMBF, the spectroscopic ellipsometry was implemented on a large scale glass deposition plant (Semco Glasbeschichtung, Neubrandenburg) and was tested during the production. The investigations show that ellipsometry is outstandingly suitable for an accurate determination of the optical layer properties of coatings on architecture glass, even for complex layer systems. Therefore, the basis for an improvement of the efficiency of the plant is given.     

Gesteinbearbeitung mittels dünner Kreissägeblätter

Treatment of stones by means of thin circular saw blades Circular saws and/or abrasive machining of granite or marble blocks takes place in the industry by block circular saws with 40 to 80 circular saw blades on a shaft. Each of these tools with a tool diameter of approx. 1,000 mm produces a kerf of approx. 6.5 mm. By use of a case‐hardened quality for the master sheets the master sheet thickness and the kerf can be reduced approx. 1 mm. Related to the block which can be separated substantial material savings result in the case of sawing of high‐quality raw materials. Because the used tools are to finish very difficulty with conventional, mechanical technologies, the laser technology became develops for stretching and arranging the disk‐shaped tools. The Laser application is a requirement for the automizableness these work procedures.     

Elektronenbeugung zur Analyse dünner Funktionsschichten

Electron Diffraction for Analysis of thin Functional Layers A short history of the diffraction techniques in crystallography is given and the basics of electron diffraction in transmission electron microscopy are explained: electrons as waves, Bragg's law, selected area and convergent beam electron diffraction. The possibilities of the often used selected area electron diffraction are demonstrated by two typical examples: determination of the crystallographic orientation in single crystalline layers (piezoelectric LiTaO₃) and phase analysis in polycrystalline structures (Ni‐Al‐O hard coatings).     

Untersuchung dünner Schichten mittels Röntgenreflektometrie

Thin film characterization by means of X‐ray reflectometry X‐ray reflectometry and diffractometry are widely used non‐destructive methods to characterize thin films in the total thickness range which is typically between 2nm and approximately 500nm. On special arrangements a resolution up to 1000nm layer thickness has been demonstrated. Layer stack morphology, surface topography, layer structure, material density, single layer or period thickness and surface and interface roughness are the typical structural parameters both of single layers and of multilayers which can be described by the measured data. The performance of the measurement setup is mainly influenced by the parameters of the incident X‐ray beam like beam divergence, monochromatism and photon energy. In the following the influence of the optical components in the beam path to angle and energy resolution of X‐ray reflectometry is discussed.     

Beitrag zum Studium des Bruchvorganges dünner Bitumenfilme

Contribution to Studies of fracture in thin bituminous films. A recently published theory of crack propagation in viscoelastic materials is briefly reviewed. This theory serves as a basis for a newly developed hypothesis describing the fracture process in thin bituminous films. Observation of fracture surfaces with the help of a scanning electron microscope showed that microcracks start from the weakest points (inhomogeneities) in the matrix. By increasing the external load disk-shaped cracks increase as a function of the applied load. Only when the critical mean crack diameter is reached macroscopie failure occurs. Fractographic methods proved to give detailed information about fracture process in thin bituminous films.     

Anforderungen und Bewertung dünner Schichten im tribologischen Einsatz

Demands and assessment of thin films in tribological applications Thin films for tribological use have been supported intensively in the last years and decades. For this reason lots of single results exist in this field of activity. But until now for engineers a handy und reliable method for the development of practical solutions is not available. The literature quoted at the end of this article deals with this problem and points out possibilities. The following paper presents selected results. Single aspects are here in this consequence only described without detailed documentation. To do this the quoted literature offers further information concerning the application of hard coatings and it refers to over 900 corresponding publications. Missing data on test parameters or boundary conditions of the test procedures as well as detailed information on all presented aspects are written down there. Tables to do selections and assessments qualify the reference as a useful handbook for the application of thin hard coatings in theory and practice. The author is pleased to help you to get the complete publication.     

Anlagenkonzept für die Abscheidung dünner Schichten durch Plasmapolymerisation

This plasma polymer layers are deposited by a plasma enhanced CVD process directly from the gas phase of an organic precursor (plasmapolymerization). Film growth rate is limited by the quantity of gas input. Plasmachemical conversion in the gas phase as well as at the film surface can be applied to affect film properties. The relation between the characteristic conversion time of the process and the application features of the plasma polymer layers lead to a vacuum technological concept for development and design making large scale applications in industry very predictable.     

Neue Möglichkeiten zur Charakterisierung dünner Schichten mit Indentermethoden

Novel Possibilities for Thin Film Characterisation Using Indentation Methods A novel methodology for the evaluation of the response of coated substrates to mechanical contact is presented which is based on the combination of a new theoretical method and high‐accuracy indentation experiments using a spherical diamond indenter. The concept may be extended in many respects and will be illustrated here only with few special examples: Using low loads, i. e. staying completely in the elastic region, the elastic parameters of film and substrate can be measured with high accuracy. When the indentation experiments is extended until failure of the coating substrate compound, the full stress and strain fields in three dimensions in the very moment of failure can be calculated. The knowledge of those fields enables one to draw conclusions on the relevant mechanisms. Once the failure mode has been identified, layer systems with optimum resistance to that failure mechanism can be found by theoretical simulations.     

Der Alleskönner der Messtechnik

The all‐rounder of measurement technology – Monitoring of vacuum properties The Novion is an all‐rounder of vacuum measurement technology. The newly developed sensor is based on a novel ion source and an integrated TOF mass spectrometer. The new vacuum measuring instrument is versatile: precise total pressure measurement over a wide range and simultaneously determination of helium partial pressure and residual gas analysis. By using the patented ion source, the instrument also achieves a high dynamic range without the use of a cost‐intensive electron multiplier, down to the UHV range. The Novion comes with a compact design, easy maintenance and an intuitive operation. The article covers the fields of application of this multi‐method sensor and explains its functionality in detail.     

Zerstöurungsfreie Prüfung dünner CFK-Laminate mit innenliegenden Fehlern

Nondestructive Testing of thin CFRP-laminates with Internal Flaws Carbon fiber reinforced plastics (CFRP) are more and more used for primary aircraft structures. Therefore, nondestructive testing is of increasing importance for quality control and maintenance. Test specimens with different flaws show the accuracy by which even very small flaws in CFRP laminates can be detected when using ultrasonic (US) and X-ray-techniques. The US-measurements (C-scans) were effected by a highly resolving US-flaw detector. Details of the system and of testing methods are described. The C-scans are compared with X-ray evaluations. Internal flaws which cannot be found in a normal X-ray image due to X-ray absorption were filled with a contrast agent (TBE); afterwards they appeared very clearly on the X-ray film. A comparison of nondestructive tests and between nondestructive and destructive tests showed a good agreement.     

EPMA‐Analyse dünner PVD‐ und CVD‐Schichten

EPMA analysis of thin PVD and CVD layers Electron Probe Micro Analysis (EPMA) is an X‐ray spectroscopic method for determining the chemical composition of solid substances in the near‐surface region. It has a high detection sensitivity, a high spatial resolution, an adjustable depth of analysis and is easy and accurate to quantify. Less well known is the fact that the EPMA is also able to analyze the chemical composition and layer thicknesses of thin multi‐layer systems non‐destructively and with only one single measurement. In particular, it is possible to determine, for example, the composition and thickness of a layer buried under one or more other layers. Conversely, with a known film thickness, the density of thin layers can be determined, a quantity that is generally difficult to access with thin layers. The following article describes the physical basics of EPMA analysis and compares them with energy dispersive X‐ray spectroscopy (EDX) and X‐ray fluorescence analysis (XRF), which are also widely used. The principle of so‐called thin film analysis for multilayer systems is explained, and the possibilities and limitations of this method are illustrated by a number of industrial application examples.     

Röntgendiagnostik plasma‐gestützt abgeschiedener dünner Schichten

X‐ray diagnostics of plasma deposited thin layers Grazing incidence x‐ray diffractometry (GIXD) and x‐ray reflectometry (XR) have been introduced as well suited tools for investigations of plasma deposited thin layers. They are non‐destructive techniques, therefore a sample can be reused and measured with other techniques. A combination of GIXD and XR can give a range of interesting information about chemical, physical and crystallographic properties of thin films. Conclusions can be drawn how plasma deposition techniques and plasma parameters influence the film growth. In three examples we present the analysis of phase and chemical composition, defect structure and measurements of kinetic process parameters.     

Funktionale Oberflächen auf Duplex‐Stahl durch Laserfeinbeschichten

Functional surfaces on duplex stainless steel by lasercladding The product‐lubricated axial and radial bearings installed in multistage high‐pressure pumps inevitably encounter severe mixed friction conditions as the pumps start and stop. This leads to extremely high tribological loads on the bearing components, compounded by the effects of a highly corrosive pumped fluid. The present paper describes a laser cladding process which produces near‐net‐shape coatings of new, highly corrosion and wear resistant functional layers which can be deposited directly on high‐alloy stainless steels without requiring additional buffer layers and without affecting the mechanical properties and corrosion resistance of the substrate. The results cover the solidification behaviour of the coatings as well as the microstructure resulting from various heat treatment conditions. In addition, the technological properties of the coatings and the resulting composites are discussed. The coating systems are tested as to their corrosion resistance and tribological characterization in a pump‐specific tribological system.     

Einsatz physikalischer Analysemethoden zur Charakterisierung von dünnen Schichten und Grenzflächen in der Halbleiterindustrie

Characterization of thin films and interfaces are necessary in semiconductor industry to ensure high yields and the required reliability of the products. Requirements to thin film and interface analysis are reviewed, and typical applications in semiconductor industry are shown. Thin film characteristics which have to be determined using physical analysis techniques are film geometry, surface and interface roughness, chemical composition, and microstructure. Advances in physical failure analysis are essential to the reduction of feature size and introduction of advanced materials and processes for future technology generations. Future trends are discussed. To reduce the time for problem solving in the manufacturing process, out of‐fab characterization tools will partly move to“at‐line” labs which are located next to or sometimes inside the cleanroom.     

Einfluss der chemischen Umgebung auf Morphologie und Struktur von Magnesiumhydroxid auf Magnesiumoberflächen

Influence of the Chemical Environment on the Morphology and Structure of Magnesium Hydroxide formed on Magnesium Surfaces Successful application of magnesium in metal construction is promoted by available methods for surface protection and, if needed, an electrical isolating layer between magnesium and other construction metals of composite materials [1]. Suitable materials for surface protection are polymer coatings, e. g. polymer paints. These coatings require a sufficiently corrosions resistant ground, which up to now normally is a environmentally dangerous, chromium‐containing conversion layer. In case of destruction of a conversion layer, caustic magnesium hydroxide is formed and responsible for a promoted delamination of various commercial polymer paints. Thus, development of a new magnesium – polymer – systems is of great interest. One probably successful possibility is a defined chemical attachment of molecular adhesion promoters to the magnesium conversion layers. These adhesion promoters should include a magnesium hydroxide specific group for a strong chemical attachment to magnesium conversion layer, which is hydrolytically stable in water, and additionally a second adhesive group at the other end of a hydrophobic spacer to ensure the attachment of a polymer. Direct attachment of these molecular adhesion promoters onto magnesium metal is not promising as all known magnesium organic compounds are hydrolytically instable [2]. As the hydroxide conversion coating is a substantial part of a magnesium‐polymer‐composite, the properties of the magnesium hydroxide layer have to be investigated and optimized depending on preparation conditions. In order to characterize the magnesium hydroxide conversion layer we use IR‐spectroscopy, quartz microbalance and Scanning Probe Microscopy. IR‐spectroscopic investigations show the presence of water in hydroxide conversion coatings formed at pH = 7–10. Conversion coatings prepared at pH > 12 are spectroscopically free of water. Taking into account the isoelectric point and the reactions resulting from a pH change, a model for the formation of the hydroxide layer is presented. This model explains the formation of a water free hydroxide layer at pH levels above 12 and the formation of water containing hydroxide layers below pH 12. The topography of the conversion layers is investigated by Scanning Probe Microscopy. If the conversion layer is formed in a solution with low pH a rough structure is built up compared to conversion layers, which are formed in solutions with high pH. These differences can be explained by taking into account the solubility of magnesium hydroxide and the change of OH⁻‐concentration in the solution due to different pH.