Über die Ausscheidung von Kupfer in Siliziumeinkristallen unterschiedlicher Realstruktur

The diffusion of copper into silicium single crystals with different real structures was investigated. Crystals were treated under various heat conditions. The deposited copper particles were recorded by infrared microscopy and by X-ray micrographs. There are specific relations to the real structure of silicium crystals which may be used for interpretation of the behaviour of some doted crystals.     

Zur plastischen Verformung von Antimoneinkristallen im Druckversuch bei Raumtemperatur

The plastic deformation of antimony single crystals dynamically tested in compression at room temperature has been investigated. As macroscopic deformation mechanisms twinning, dislocation slip, and kinking have been observed. The critical resolved shear stress for basal slip and twinning was measured and the orientation dependence of the deformation mode was explained. It is shown that basal slip dominates compared to rhombohedral slip.     

Gittergeometrische Betrachtung der plastischen Verformung von Lavesphasen

The brittleness of many intermetallic compounds even of those of metallic bond is supposed to be related to the lattice geometry. The influence of the arrangement of atoms on slip of dislocations has been investigated in case of the Laves phase lattices of MgZn₂ (C 14)- and MgCu₂ (C 15)-type of structure and is compared with the close packed lattices of metallic elements. Changes of coordination during slip, interpenetration of lattice planes in a hard sphere model, possible stacking faults, and partial dislocations have been considered. From there the most favourable slip planes are derived for dislocations of the following characters: perfect dislocations of stable Burgersvectors and Burgersvectors indifferent to dissociation and imperfect dislocations. The formation of interstitial atoms during intersection of moving edge dislocations is suggested. In comparison with the elemental lattices the brittleness of compound lattices is concluded to be a consequence of the complicated arrangement of atoms.     

Eine neue Methode zur Verformung durch Zugbeanspruchung im Emissionsmikroskop

As an additional device for the emission microscope EF-Z6 of the VEB Carl Zeiss, Jena, a tensile rod is described, being able at high temperatures sheet metal specimens to be deformed up to tearing. Studies on recrystallization of aluminum and soft steel are reported. These examples demonstrate the good usability of the tensile rod for immediate study of the formation of nucleis the grain boundary migration and other problems of the warm deformation of technical alloys in the emission microscope. Briefly two other additional apparates are reported, i.e. a dilatometer for continuous temperature measuring, and an oscilloscope screen for producing undistorted film or TV imager.     

Zur Abbildung von Isolierschichtdefekten im Elektronenspiegelmikroskop

Following the investigations on the imaging behaviour of homogeneous dielectric layers considerations on the possibilities of imaging simple layer inhomogeneities are discussed. These considerations imply a contrast amplification by charging phenomena. By definite variation of the substrate potential a distinction between geometrical layer defects (protrusions, indentations, holes) and electrical inhomogeneities of the insulating layer (regions of increased and decreased conductivity, resp.) is possible as shown by the experimental investigations. Criterions for distinguishing different cases can be given. The sensitivity for detecting inhomogeneities in non-covered dielectric layers is higher than in the case of those being covered with a conductive layer.     

Untersuchung gestörter Oberflächenschichten an Siliziumeinkristallen

It has been proved that by densitometric measurements of reflections of Kikuchi photograms a numeric value can be found for the quality of polished surfaces of Si single crystals. This value is given by the proportion ΔS₁/ΔS₀, characterizing the relation of the initial state of surface and the state of deeper layers, not being affected by mechanical working. This method enables to estimate the quality of crystal surfaces.     

Ein Beitrag zur Herstellung von Galliumarsenid-Epitaxie-Schichten im Hochvakuum

GaAs-films have been vacuum deposited on air cleaved NaF-, NaCl-, NaBr- substrates by the technique of Howson (evaporation from one single source). It was stated that the results obtained with our apparatus were not sufficient reproducible. Optimum orientation effects were achieved with a deposition rate of 15 Å sec⁻¹ and with a substrate temperature of ∼300 °C. The temperature of structural change from amorphous to cristalline phase was evaluated to be nearly equal for NaCl and NaF at 250 °C. Particularly in the systems GaAs/NaCl and GaAs/NaBr remarkable orientation effects were observed.     

Keimbildung von Saccharoselösungen im Schallfeld

Sonic waves from a generator based on mechanical vibrations influenced the nucleation of sucrose solutions of various supersaturations and temperatures. Solutions were kept inside sealed glass tubes. There is an optimum frequency of 7.1 kHz showing the greatest influence on the shortening of the time of nucleation. With increasing temperature this time decreases. The difference in the behaviour of normal and sound agitated solutions increases with supersaturation and temperature. The nucleation of sound agitated solutions may be shortened in this case manifold. The influence of sonic waves enables to get regular formed crystals.     

Tempern von Cd0,2Hg0,8Te im Quecksilberdampf

N-type Cd_0,2Hg_0,8Te with a minimum concentration and a maximum mobility of charge carriers serves as starting material for the production of photoconductive infrared detectors with high sensitivity. The number of the defects, originating in Cd_0,2Hg_0,8Te during crystal growth, can be considerably diminished by a heat treatment in saturated mercury vapour. Details of the preparation and the accomplishment of the annealing essays as well as the results of the experiments are described.     

Untersuchungen zur orientierten Verwachsung von Gold mit Alkalihalogeniden im UHV

In the present paper the oriented overgrowth of Au on alkalihalides in ultra high vacuum has been investigated. The result was, that in contradiction to high vacuum experiments no perfect orientation of gold on rocksalt was observed. The epitaxial temperatures for Au on KCl, KBr and KJ were higher than reported for experiments in high vacuum systems and were a function of the deposition rate. The influence of the local temperature shift, coased by the condensation energy, of amorphous layers on the surfaces and the procedure of evaporation has been investigated.     

Emissionsmikroskopische Untersuchungen zur plastischen Verformung und Versetzungsmarkierung an NbFe2

By means of a homogenous compression device the Laves phase NbFe₂ was deformed plastically while being observed in an emission electron microscope. In connection with these experiments the possibility of marking dislocations was investigated emerging from the crystal by means of a thermal treatment under vacuum conditions in the emission electron microscope. Slip traces on the surfaces were observed only above a critical temperature (transition brittle-ductile). During a high temperature treatment under vacuum oxide nuclei grow on the surface. These nuclei seem to decorate dislocations emerging from the crystal. On surfaces of plastic deformed samples the oxide nuclei mark slip traces.     

Beitrag zum lichtmikroskopischen Nachweis von Versetzungsnetzwerken nach thermischen Behandlungsschritten im Silizium

Dislocations and dislocation networks arranged at small angles respective to and directly under the surface of single crystal silicon samples were revealed by an etching technique in combination with enhanced contrast microscopic inspection. Etch patterns generated in thermally treated silicon wafers are discussed.     

Chemischer transport im nichtisothermen plasma; bildung von ain- und tin-kristallen

The chemical transport of carbon, aluminiumnitride and titaniumnitride was studied in a non-isothermal low-pressure plasma. It was shown, that under this conditions chemical transport was possible even in such systems in which chemical transport is not possible without application of a plasma. Stoichiometric AlN was obtained in the form of powder or crystals up to 0.5 × 0.5 × 3 mm³.     

Modulationsabhängige Inklination im Fernfeld von GaAs-Lumineszenzdioden vom Fabry-Perot-Typ

The dependence of the transverse far field intensity distribution of GaAs lightemitting diodes on the ac-frequency is studied. The used four-layer-step-discontinuity of the dielectric constant influenced by the free-carrier absorption is modified in that the region of light creation and the wave guide region are assumed to be separate. The so calculated inclination of the maximum far field intensity direction in comparison with the plane normal to the light emitting surface of the diode decreases with increasing modulating frequency. The frequency influence on the phase homogeneity of the radiated light is shortly mentioned.