Double conical beam-rocking system for measurement of integrated electron diffraction intensities

Publisher Summary In energy-filtering transmission electron microscopy (EFTEM), the zero-loss electrons or electrons passing an energy-loss window of the electron energy-loss spectroscopy (EELS) are used for image formation. This can be achieved by using the scanning mode in a dedicated scanning transmission electron microscope (STEM) or in a TEM with a spectrometer behind the camera chamber or by using an imaging filter lens in the column of a TEM. The conventional TEM and STEM modes can be combined in this way with the mode of electron spectroscopic imaging (ESI) and electron spectroscopic diffraction (ESD), and different modes can be used to record an EELS spectrum. An EFTEM can therefore make full use of elastic and inelastic electron-specimen interactions. This chapter provides an overview of the physical background and the possibilities of EFTEM. The relevant physics of elastic and inelastic scattering is also discussed followed by the instrumentation of EFTEM. The theoretical approaches for understanding the contrast and examples of application are presented for ESI and for ESD.

Energy-filtering transmission electron microscopy

Modern microelectronic devices have nanoscale features that dissipate power nonuniformly, but fundamental physical limits frustrate efforts to detect the resulting temperature gradients. Contact thermometers disturb the temperature of a small system, while radiation thermometers struggle to beat the diffraction limit. Exploiting the same physics as Fahrenheit's glass-bulb thermometer, we mapped the thermal expansion of Joule-heated, 80-nanometer-thick aluminum wires by precisely measuring changes in density. With a scanning transmission electron microscope and electron energy loss spectroscopy, we quantified the local density via the energy of aluminum's bulk plasmon. Rescaling density to temperature yields maps with a statistical precision of 3 kelvin/hertz(-1/2), an accuracy of 10%, and nanometer-scale resolution. Many common metals and semiconductors have sufficiently sharp plasmon resonances to serve as their own thermometers.

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Nanoscale temperature mapping in operating microelectronic devices

Solid state excitations by electrons

Origin of the Characteristic Electron Energy Losses in Magnesium

Es werden Experimente beschrieben, in denen mit Hilfe der Gegenfeldmethode die Abhangigkeit des mittleren Energieverlustes von der Objekttemperatur an Al und Ge gemessen wurde. Die Ergebnisse stimmen mit der Aussage uberein, die sich aus der Plasmatheorie bei Berucksichtigung der thermischen Ausdehnung des Kristalls ergibt. Weiterhin wurden Form, Lage und Intensitat der Energieverteilung der unelastisch gestreuten Elektronen in Abhangigkeit vom Streuwinkel untersucht. Auch hier konnten an Al die Aussagen der Theorie hinsichtlich der Grose des Verlustes und des maximalen Streuwinkels bestatigt werden.

Über die Abhängigkeit der charakteristischen Energieverluste von Temperatur und Streuwinkel

In a previous paper direct electron-intensity measurements in Debye-Scherrer diagrams of aluminium have been described. A retarding field apparatus was used for investigations into the influence of crystal size and electron energy (15 to 50 keV) on the elastic diffraction intensities. The validity range of the kinematical theory could be determined. By means of a retarding field the inelastically scattered electrons were separated from the elastically scattered electrons (energy loss below 2 eV). In this paper the retarding field apparatus by which scattering intensities can be measured with good accuracy (≈ 2%) is described in detail. It is compared with other arrangements for the measurements of angular and energy distributions of scattered electrons.

Eine Gegenfeldanordnung zur Messung von Energie- und Winkelverteilungen gestreuter Elektronen

By means of a retarding field apparatus the electron diffraction intensities of a polycrystalline Aluminium-foil have been measured for different electron energies between 17 and 50 kev. The specimen was kept at 154 °K and the thickness of the crystallites was about 280 A. It has been shown that the high index reflections behave kinematically, while the first order reflections [e.g. (111), (200)] are much influenced by dynamical extinction effects which can be explained very well by the dynamical two beam approximation.

Messung der Elektronenbeugungsintensitäten polykristalliner Aluminiumschichten bei tiefer Temperatur und Vergleich mit der dynamischen Theorie

Absolute intensity measurements of the electrons scattered by a polycrystalline Aluminium foil were carried out in the energy range between 25 and 50 keV. The electrons scattered elastically were separated from those scattered inelastically by means of a retarding field. The intensities of the electrons having passed the foil unscattered and of those which were scattered elastically into the Debye-Scherrerrings and into the continuous background can be interpreted by the assumption of reasonable thicknesses of the crystalline Aluminium and the amorphous Aluminium-Oxide. These values agree approximately with the thickness measured by light absorption. Additionally the probability of the inelastic scattering process can be deduced from these measurements. Investigations of the angular distribution were carried out in order to study the influence of the inelastic scattering on the shape of the primary beam, the rings and the continuous background. The results are discussed in detail. Some results are given in particular, concerning the increase of the half width of the rings due to inelastic scattering processes.

Wirkungsquerschnitt und Winkelverteilung der elastischen und unelastischen Elektronenstreuung in Aluminiumschichten

A retarding field apparatus for the measurement of angular and energy distributions of scattered electrons (15 to 50 keV) is described. The apparatus was used for investigations into the influence of crystal size and electron energy on the elastically scattered intensity in Debye-Scherrer-diagramms of aluminium. The results are discussed with respect to the dynamical and kinematical theory. It proves, that the kinematical theory does not hold for crystallites of 100 A thickness or more.

G. Meyer

Papers

Über die Abhängigkeit der charakteristischen Energieverluste von Temperatur und Streuwinkel

Eine Gegenfeldanordnung zur Messung von Energie- und Winkelverteilungen gestreuter Elektronen

Messung der Elektronenbeugungsintensitäten polykristalliner Aluminiumschichten bei tiefer Temperatur und Vergleich mit der dynamischen Theorie

Wirkungsquerschnitt und Winkelverteilung der elastischen und unelastischen Elektronenstreuung in Aluminiumschichten

Messung der Intensitäten von elastisch und unelastisch gestreuten Elektronen mit einer Gegenfeldanordnung