Practical Metallography Volume 42 Issue 4

Practical Metallography

Volume 42 Issue 4

Contents
Journal Overview

Herausforderungen an die TEM-Probenpräparation

Ehrenfried Zschech June 11, 2013 Page range: 159-160

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Elektronenmikroskopische Untersuchungen an mit FIB-Präparation hergestellten Grenzflächen von biologischen Materialien und Werkstoffen: erste Ergebnisse

C. Burkhardt, W. Nisch June 11, 2013 Page range: 161-171

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Abstract

Kurzfassung Für die Untersuchung der Ultrastruktur von biologischen Zellen und Geweben ist die Elektronenmikroskopie ein wichtiges Hilfsmittel. Damit mit dieser Methode auch die Grenzfläche von biologischen Systemen und Werkstoffoberflächen gezielt untersucht werden kann, wurden in der vorliegenden Arbeit klassische Methoden der biologischen Präparation, die kritische Punkt- Trocknung und das Einbetten von kontrastierten Zellen in einem Polymer mit der Focused-Ion-Beam-Technik (FIB) kombiniert. Die Arbeiten wurden in einem Zwei-Strahl-Gerät durchgeführt, so dass die FIB-Präparation eines Querschnitts bei hoher Auflösung im Rasterelektronenmikroskop beobachtet werden kann. Es wird gezeigt, dass es möglich ist, Zellen und die Kontaktstellen der Zellen zu einem Substrat auf einer Sub-Mikrometer-Skala zu präparieren und abzubilden.

Focused Ion Beam Preparation and EFTEM/EELS Studies on Vanadium Nitride Thin Films

Michael Rogers, Gerald Kothleitner, Antje Berendes, Wolfgang Bock, Bernd O. Kolbesen June 11, 2013 Page range: 172-187

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Abstract

A two-beam focused ion beam (FIB) instrument was used to prepare transmission electron microscopy (TEM) specimens of vanadium nitride layers produced by rapid thermal processing in a NH3 or N2 atmosphere. For the FIB preparation method an in-situ liftout technique was used, which was found to be highly efficient regarding specimen transfer yield but also very convenient as the final milling steps were carried out with the TEM specimen already fixed to the TEM grid. Electron energy-loss spectroscopy (EELS) and energy-filtering TEM (EFTEM) was applied to characterize the films morphologically and chemically. EFTEM investigations provided chemical information over the whole film thickness and revealed that the vanadium nitride layers consisted partly of two different nitride phases. By interpreting the EELS near edge structure of the nitrogen K-edge and comparing them to high-resolution spectra recorded on a monochromator TEM at an energy resolution of ∼0.25 eV, the nitride layers could be unambiguously identified.

Focused Ion Beam (FIB): Applications in Micro- and Nanoanalysis in Geosciences and Applied Mineralogy

Richard Wirth June 11, 2013 Page range: 188-205

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Abstract

Recently the focused ion beam (FIB) tool has been successfully used to prepare site-specific geological specimens for subsequent analysis by TEM, and as a stand-alone instrument for micromachining of materials such as diamond. FIB enables to prepare a TEM foil from the specific location of interest. TEM foils with the dimensions 20 × 10 × 0.150 micrometer can be cut from nearly any sample by means of a Ga-ion beam. The preparation of a TEM-ready foil with similar dimensions takes about 4 hours in a fully automated process, which is significantly faster than conventional argon ion milling. It is this unique possibility of site-specific TEM foil preparation, which enables TEM investigation of submicron-sized mineral inclusions in mantle minerals such as diamond, garnet or olivine, thus providing an insight into the pressure-temperature conditions and chemical composition of the Earth's mantle during formation of the encapsulating minerals. A FEI FIB200 instrument is operated at the GFZ Potsdam since more than two years and TEM foils from many rock-forming minerals such as olivine, garnet, pyroxene, amphibole, quartz, apatite or glass, metals, ceramic materials and even microfossils have been successfully prepared and subsequently investigated by TEM. The first finding of nanometre-sized diamond aggregates in melt inclusions enclosed in a silicate mineral (pyroxene) in mantle xenoliths from Hawaiian lavas illustrates the enormous potential of this technique. Another novel application of FIB in geosciences is micromachining diamonds, which are used for high-pressure diamond anvil cells (DAC).

TEM-Zielpräparation unter REM-Beobachtung mittels Zweistrahl-FIB

Frank Altmann June 11, 2013 Page range: 206-212

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Abstract

Kurzfassung Die Transmissionselektronenmikroskopie (TEM) ist eine wichtige Untersuchungsmethode und wird industriell zunehmend für die Charakterisierung der stetig kleiner werdenden Strukturen mikroelektronischer Bauelemente eingesetzt. Die dafür notwendige Zielpräparation wird im wesentlichen mittels fokussierender Ionenstrahltechnik (focused ion beam, FIB) durchgeführt, wobei die Anforderungen an Präzision und Qualität der hergestellten TEM-Proben ständig wachsen. Insbesondere spezielle TEM-Techniken, wie Elektronenenergieverlustspektroskopie (electron energy loss spectroscopy, EELS) und höchstauflösende TEM aber auch scanning-TEM (STEM) im Rasterelektronenmikroskop (REM) erfordern geringste Probendicken bei minimaler FIB-Strahlschädigung. Mit der Möglichkeit einer REM-Beobachtung der FIB-Bearbeitung in modernen Zweistrahl-FIB-Anlagen können TEM-Proben noch präziser als bisher zielpräpariert werden.

About this journal

Practical Metallography is a bilingual (German-English) journal that informs you thoroughly on materialographic preparation, imaging and analysis of microstructures. The journal covers the development and improvement of metallographic methods and equipment, possibilities of optical and electron microscopy, spectroscopy, diffraction techniques, non-destructive testing, metallographic investigations of materials, problems of specimens preparation and evaluation including useful laboratory advice and recipes, failure analysis including damage detection and elimination.
All articles are subject to thorough, independent peer review.
Practical Metallography works closely with Deutsche Gesellschaft für Materialkunde e.V. (DGM)