Oberflächenbeurteilung von bearbeiteten Siliziumscheiben

For the judgement of various polished surfaces of silicon single disks was used the method of reflexion high energy electron diffraction (RHEED) in the electron microscope and on the other hand the X-ray-method of double crystal spectrometry. Because of the obtained diffraction pictures and the obtained rocking curves and because of the completing figures of surfaces with the replica method on the electron microscope, it is possible to estimate the silicon single disks relating to the mistakes in the surface range.     

Über eine optische Methode zum qualitativen und quantitativen Nachweis von Oberflächenfehlern

The principle of the optic edge method is used for qualitative and quantitative judgment of polished single crystal disks. With the help of simple reflections hints at the nature of mistakes and estimation of the vertical intervals, respectively, can be ascertained. For the application of this procedure into the supervision of production conditions for a constructive solution are reported allowing a simple testing of polished surfaces.     

Beziehungen zwischen Beilbyschicht und Oberfläche fester Körper

The investigation of the influence of the Beilbyschicht upon thin plates begins with the statement of the distortion of the plate by calorification during its generation. The enhancement of the temperature of the material curves the middle surface of the thin plate into a thin shell. The curvature exist after plates being cooled.     

Anwendungsmöglichkeiten der Röntgentopographie zur Bestimmung der Oberflächengüte und der Realstruktur von Granateinkristallen

Single crystals of garnets of the rare earth are interesting in the development of bubble memories. Therefore it is necessary to controll the surface quality of the substrates and epitaxial layers during the different steps of preparation. X-ray topographic methods for testing the surfaces will be compared with the etching technique. Loop-configurations at inclusions are described and the mechanism for their formation will be discussed.     

Morphologische Untersuchungen an Oberflächenschichten von Stahl nach einer Drehbearbeitung

The surface morphology of machined steel C60 was investigated by comparative scanning electron micrographs and surface finish measurements. Structure changes in the boundary layer by plastic deformation could be examined using optical and electron optical observation of longitudinal cut taper sections. Both the surface roughness and the depth of changes by plastic deformation were found to increase with progressing wear of the tool. Concluding it can be stated that the additional application of scanning electron microscopy reveals more detailed informations than usual test methods alone cal deliver.     

Oberflächenstörungen und Hohlwachstum bei der Züchtung von β-Kupferphthalocyanin-Einkristallen aus der Gasphase

Hollow crystals are obtained frequently during the growth of copper phthalocyanine single crystals from the vapour phase. This appearance makes some physical investigations impossible. To overcome these difficulties some ways are discussed. The reasons for hollow growth are instabilities in the growth caused by diffusion controlled inhomogeneities in supersaturation on the growth front. This was found by observations of surface defects and by defined growth experiments. By introduction of special methods of growth and use of defined parameters one obtains bulk crystals of larger extent up to 1 mm in cross direction. References are given in the field of hollow crystal growth in the vapour phase of other substances.     

Oberflächeneffekte an Silizium-Einkristallen

Structures of different geometry were observed on surfaces after diffusion or annealing of Si planar slices in vacuum or non-oxidizing atmosphere. Characteristic etch structures were found after arsenic diffusion under determined experimental conditions. Traces of water are considered to be the cause for the levels.     

Zum Wachstum von AIII-BV-Verbindungen aus nichtstöchiometrischen Schmelzen (III) Untersuchungen zur Flächenmorphologie homoepitaktischer GaAs-Schichten

The morphology of a surface with the formation of GaAs-layers from Ga solutions is caused by the primary formation of characteristic holes. The reason for the origin of such holes is explained by small stresses resulting from small lattice mismatches.     

Der Zusammenhang zwischen Oberflächenbehandlung und Barrierenhöhe bei metallkontaktiertem GaSb

Barrier heights of Ag-, Au-; Ni-, Al-; In-, Sn-contacts onto p- and n-GaSb surfaces were investigated by measuring the current-voltage characteristics. Barrier heights depend on surface conditions of semiconductor and contact metal. The results were explained by surface states, terms of trap and interfaces of chemically and mechanically polished (111) surfaces. They are due to the specific differences in the boundary conditions at the metal-semiconductor contacts and determine the quality of contacts. Sn-, Al-, Ag-contacts have „ohmic”︁ characteristics on n-GaSb, Au- and In-contacts became „ohmic”︁ contacts on chemically polished surfaces.     

Die Bedeutung mechano-elektrischer Erscheinungen für die Bestimmung der Oberflächenenergie von Kristallen

Using the method of crystal cleaving a calculation of the surface free energy of mica is given. For this an effective elastic stiffness constant is introduced, this taking into consideration the electrostatic charging of the crystal surface. For measuring the charges arising from the cleaving of the crystal a special experimental equipment is used. Microgeometry and mechano-exoelectronic flow are determined. With sufficient high vacuum the latter becomes the main process of stabilizing instable electric crystal surfaces. The electrostatic charging only little affects the values of measured surface energies. The deformation, however, of layers near the surface gives a larger effect. Considering this deformation a surface free energy of 380 erg · cm⁻¹ for mica is given.     

Präparation und Charakterisierung von Granateinkristalloberflächen

The preparation of single crystal substrates of gadolinium gallium garnet as a typical example of a brittle material is described. The mechanical polishing with iron oxide and diamond as well as a mechano-chemical polishing procedure basing on SiO₂/H₃PO₄ are investigated. Working damage is investigated by X-ray topography, double crystal spectrometry and selective etching. Results are discussed in the frame of a brittle fracture model of the abrasion process.     

Bildung von paramagnetischen Defekten in SiO2-Glas nach Oberflächenbehandlung im Niederdruckplasma

Low pressure plasma treatment of SiO₂-glass produces paramagnetic defects in SiO₂ volume. The defects are similar to those created in quartz (glass or crystal) by neutrons or γ-radiation. As a cause of defect formation taking place only in glassy and not in crystalline samples plasma radiation is proved. From dependence of defect concentration on conditions of formation (plasma parameters, time of treatment) a complex mechanism of formation will be concluded. The depth distribution of defects refers to their diffusion in SiO₂ volume.     

Strukturuntersuchungen an Oberflächenschichten spanend bearbeiteter Molybdän-Einkristalle

Molybdenum single crystals were used as model samples for gross machining operations (turning). The damaged surface layer was studied by reflection electron diffraction and transmission electron microscopy (TEM). Near the machined surface the material was found to be polycrystalline, the transition to the single crystal state occurs within the range from 2 to 5 μm. Pronounced plastic deformations are ranging to a depth of about 150 μm below the surface. The transition to the undisturbed single crystal occurs within the range from 150 to 300 μm.     

Gitterkonstantenänderungen und chemische Inhomogenitäten von tetragonalem ZnSiP2

X-ray lattice parameter measurements in small specimen volumes of ZnSiP₂ crystals by means of the Bond method demonstrate local chemical inhomogenities probably caused by changes in Si concentration up to about 0.8 atomic p.c.     

Über den Zusammenhang zwischen Kompressibilität und Härte von Mineralen und nichtmetallischen kristallinen Substanzen

An attempt is made to find out an experimental correlation between diamond pyramid microhardness number HV (according to Vickers) and compressibility χ of nonmetallic intrusion substances. By means of thermoelastic considerations, especially with respect to diamond and related to the bonding theory of crystals, a logarithmic plot of χ (log HV) yields a group of straight χ-lines. Further, as a technical consequence, a computation formula is given for conversing Mohs' hardness test numbers to HV-numbers and vice versa.     

Bestimmung von Diffusionskoeffizienten aus der Röntgen-Kleinwinkelstreuung und Lichtstreuung von Gläsern

It is shown how to conclude from small angle X-ray scattering and light scattering of phase separated glasses what kind of phase separation process is occurring in the glass. In the cases of diffusion controlled particle growth and of spinodal decomposition, methods were presented permitting to find out from diffraction experiments the diffusion coefficients underlying these decomposition processes. The methods were demonstrated with three different glasses.     

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.