Stofftransport durch Schichtsysteme aus Polymeren und dünnen anorganischen Schichten

Mass transport through layer systems consisting of polymers and thin inorganic layers Flexible layer systems from polymeric substrates, thin inorganic layers deposited by vacuum coating and additional polymeric layers are frequently in use to obtain high barrier properties, predominantly against oxygen and water vapour. Especially in cases where additional polymeric coatings are able to fill defects in the inorganic layers, barrier properties of the resulting layer systems show a stronger dependence on their thickness. For the transport of condensable substances, especially of water vapour, an additional porosity in the sub‐nm‐size can be assigned to the inorganic layers. This, however, has a negligible effect on gas permeation. Multilayer structures made from substrates and alternating polymeric and inorganic layers show much better barrier properties than single polymeric substrates coated with single inorganic layers. These improvements, however, are less than previously reported here. Moreover, also in these cases, the condensation of water vapour in sub‐nm pores gives much higher rates for the permeation of substances than expected from simple defect models.     

Optisch dünne Schichten mit kontrollierten Eigenschaften durch plasmaunterstütztes Magnetronsputtern

Optical thin films with controlled properties by plasma enhanced magnetron puttering A new reactive magnetron sputter process was investigated in which an additional plasma source was implemented to support the magnetron sputter process. The plasma source is determined by high ion current density and moderate ion energy. At the beginning of the work, extensive investigations of the interaction of the magnetron with the plasma source during the deposition process were performed. Also, the plasma parameters in the region of the substrate were determined. A stable process which can be controlled very precicely was obtained with the set‐up used here. In the following, different oxide materials such as zirconia (ZrO₂) and titania (TiO₂) were deposited and investigated. It shows that because of the precise process control, different optical and morphological properties can be directly influenced by tuning the ion‐to neutral fraction of the process.     

Optisch dünne Schichten aus Sicht eines Anwenders

Optical thin films are used for example, in precision optics. Their effect is important for lenses with many elements. In special plants, materials are evaporated in order to deposit to a thin film on substrates. Cleaning before and smoothing after deposition are also steps in thin film production. Because of its advantages, ion-assisted deposition of cold substrates overcomes conventional physical vapour deposition of heated substrates.     

Plasma und Dünne Schichten

Plasma and thin films for lighting application Thin films play an important role in the lighting industry. Well known products are reflectors with simple aluminium coating or with dichroic coatings for cold light mirrors. Especially for energy saving applications special halogen bulbs are coated with a transparent hot mirror that increases the overall efficiency up to 50 % while keeping the positive properties of halogen lighting like color, color rendering index, start up performance and others unchanged. Special thin film applications realize color filters, IR filters, UV filters or color conversion filters. All these processes are vacuum processes that work with plasma assistance. The most prominent technologies for cost effective production are the PICVD processes (former development of SCHOTT AG in cooperation with Auer Lighting) and the Microdyn® technology from DSI, Santa Rosa.     

Keimbildung und Wachstum von TiO2 in dünnen Schichten

Nucleation and growth of TiO₂ in thin films The morphology of thin films of TiO₂ reflects the whole production process. Rutile nuclei are generated by bombardment of the growing film with particles with an energy of about 100 eV, presumably by subplantation. Anatase grows faster in amorphous films, due to lower mechanical stress. Evaporated films are metastable at room temperature and can get reproducible optical properties by postheating at the deposition temperature. The increase of the refractive index with increasing mass density cannot be described with a ClausiusMosotti approach, due to the inhomogeneous structure of the films.     

Dünne Schichten durch Deposition unter streifenden Einfall

Micro‐ and nanostructured thin films by Glancing angle deposition Physical vapour deposition under conditions of obliquely incident flux and limited adatom diffusion results in films with a columnar microstructure. These columns will be oriented toward the vapour source. An additional substrate rotation can be used to sculpt the columns into various morphologies (slanted and vertical posts, chevrons, screws or spirals). With this glancing angle deposition (GLAD) technique can prepared porous thin films with engineered structures from a variety of dielectric, semiconducting and metallic materials. The paper presents the In this paper the physical fundamentals of the GLAD technique are introduced, the production of micro‐ and nanostructures of different morphology on non‐patterned and patterned substrates is demonstrated and some possible applications of this new deposition technique are introduced.     

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.     

Nanostrukturierte dünne Schichten mit Giant Magnetoresistance (GMR) Effekt für Sensoranwendungen

Nanostructured Thin Films with Giant Magnetoresistance (GMR) Effect for Sensor Applications The basics of the Giant Magnetoresistance (GMR) effect in thin films prepared by evaporation in ultra high vacuum or by sputtering are explained and different GMR‐systems are presented. Applications of the GMR and the related TMR (Tunneling MR) effect can be found in sensor applications as well as in information and data storage technology.     

Eine neue Methode zur Festigkeits- und Zähigkeitsbestimmung von dünnen Schichten

A New Method of Determining Strength and Fracture Toughness of Thin Films A method is presented for measuring strength and fracture toughness of thin films. The basic idea of this method is to use a compact steel specimen as a substrate, which is deeply precracked by means of fatigue loading prior to the coating process. Under bend loading of this composite crack opening occurs accompanied by straining the free-standing thin film which bridges the crack. Film rupture firstly occurs at the front face of the specimen followed by crack growth on both sides. The film properties can be derived by eliminating the substrate effect through determining the difference between the two load-displacement curves corresponding to the intact and the damaged film, respectively. The strength of the film can be calculated from the load difference at film rupture at the front face of the composite. The fracture toughness is evaluated from load and compliance change during successive crack growth on both sides of the specimen. First results on PACVD TiN-films are presented and compared with available bulk data, thus demonstrating the applicability of the proposed method.     

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.     

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.     

Dünne Schichten für die Optik und Kristallherstellung in Oberkochen von 1946 bis heute

Thin films in optics and the growing of optical crystals are strongly related to the high vacuum technology. The development of this technology by Carl Zeiss at Oberkochen since 1946 until now is reported in this paper.     

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.     

Stofftransport durch polymere und anorganische Schichten

Polymeric materials are to be found in an increasing number of applications. In many areas, however, their high permeability for substances such as gases or water vapour creates problems. Traditionally, additional barrier layers are deposited onto the polymeric substrates as a permeation barrier, i.e. as a barrier against the transport of substances. Typically, polymeric layers are deposited from solution in atmospheric pressure, inorganic layers in vacuum processes. Highest barrier properties can be achieved via multi layer systems from inorganic and organic layers. This article describes basic principles of the permeation of substances through layer systems, highlights the differences of the substance transport through polymeric materials and inorganic layers and gives consequences for the production of materials with high and ultra‐high barrier properties, on the basis of polymeric substrates     

Funktionelle Schichten durch UV‐ und Elektronenstrahlhärtung

UV (EB) Curable Functional Coatings Composition, curing kinetics and application potential of acrylate based UV(EB) curable coatings are described. To formulate these coatings a manifold of acrylate oligomers exhibiting either ether, ester, epoxy or urethane functionality can be used as binders whereas acrylate monomers are applied as reactive thinners. Coatings with special functional properties such as resistance against chemicals, scratch and abrasion resistance, UV‐protection and flexibility can be applied on substrates such as paper, plastic films, wood and engineered wood, aluminum etc. Additionally, liquid acrylates can be favourably applied to produce microstructured or super smooth surfaces: the acrylate is brought into contact with either a structurized or a polished drum and rapidly cured in contact with the cylinder surface. Scratch and abrasion resistant coatings are obtained from acrylate nanocomposites. These formulations contain up to 30 w% SiO₂ nanoparticles covered by a polysiloxane shell.     

Charakterisierung von Schichten und Platten

Characterization of layers and sheets – nondestructive and contactless testing with the help of microwaves With the help of microwaves a variety of materials in the form of layers, plates, or objects of complex geometry can be characterized in terms of their material properties, geometry and defects. The test is non‐destructive and can be performed quickly and without contact. In transmission mode non‐metallic and electrically slightly conductive materials can be investigated with a thickness of up to several cm while in metallic materials the testable thickness is in the micronand nanometer‐range. In reflection mode materials with higher electric conductivity can be tested, too.