Abstract: A method for pulling silicon semiconductor rods, in particular having diaers of 10cm and over. The current methods of crucible-free float zoning or float zone pulling can be markedly improved if the molten cap like zone which develops is forced inwardly in the growth process. This is accomplished with the aid of electromagnetic forces in an annular zone situated opposite the coil slot. The electromagnetic forces can be achieved by using induction heating coils whose coil surface facing the molten cap is provided with annular segments whose thickness increases from their inner periphery ouotwardly and which are disposed opposite the coil slot above the peripheral region of the molten cap.

Abstract: A process for the sawing of crystal rods or blocks into thin wafers by innal-hole saws is specified. In this process, the deviation of the saw blade from the intended cutting line, occurring in virtually every sawing operation, is countered by the force of a fluid being applied, at least periodically, to the side surfaces of the blade. This allows the force conditions in the saw cut and thus the deflection of the saw blade, to be influenced. This process results in an improved geometrical quality of the wafers obtained and in prolonged service life of the saw blades which have to be resharpened less often.

Abstract: A process and apparatus for the manufacture of silicon rods having a colur structure comprising monocrystalline crystal zones with a crystallographic preferred orientation. Molten silicon is transferred from a silicon reservoir into a crystallization chamber which is formed by rollers arranged in a leak-proof manner in the shape of the desired rod cross-section. There the silicon first forms a stable outer shell of solidified material and, while it continues to crystallize, it is withdrawn at the bottom and released by the rollers. Owing to the short period of contact with a vessel wall a silicon rod is obtained that is particularly free of impurites.

Abstract: A multi-blade inner hole saw for the sawing of crystal rods or blocks, such as solar cell base material on a silicon base, into thin wafers has saw blades arranged mirror-symmetrically with respect to the bearing on either side of a common drive cylinder. In the sawing operation, the workpieces are sawn synchronously by the saw blades.

Abstract: Cutting-off tools whose cutting edge has a cutting layer with a bonded cutting grain are sharpened by sawing momentarily into a solid sharpening substance, in which case, in addition to a relative movement between cutting edge and solid material corresponding to the sawing operation, an oscillating relative movement transversely thereto is also performed. The process is used with particular advantage in combination with processes for the centerhole sawing of semiconductor or oxidic material.

Abstract: An induction heating coil for a zone pulling of semiconductor rods assures the disturbance-free performance of the pulling process even at the high power densities required for large rod diameters (approximately 10 to 12 cm). According to the invention, the arc-over paths between surfaces in the region of the coil slot, which are at differing potentials, are covered by one or more movable planar structures of temperature-stable insulating material which are introduced into the coil slot.

Abstract: A process is provided for bilateral abrasive machining of wafer-like workpieces, especially semiconductor wafers. The process uses carrier disks in which the outer periphery on which the driving forces mesh, is made of a material having a tensile strength of at least 100 N/mm.sup.2, while in the area that comes into contact with the workpieces to be machined, there is provided a plastic material having an elasticity modulus of from 1.0 to 8.10.sup.4 N/mm.sup.2.

Abstract: A process and apparatus for the regeneration of shaped carbon, and especially graphite, bodies used in the presence of molten silicon. The shaped bodies are heated in an inert atmosphere to a temperature in the range of from 1700.degree. to 3000.degree. C. and maintained at this temperature for a defined period of time. The process substantially prolongs the service life of the shaped bodies. The apparatus includes at least one evacuable loading chamber, and evacuable heatable heating chamber connected to the loading chamber and an evacuable coolable cooling chamber connected to the heating chamber. A support capable of moving between the loading, heating and cooling chambers is adpated for receiving the shaped bodies to be regenerated.

Abstract: In a process for protecting polished silicon surfaces, after an oxidative eaning is carried out, the surface is coated with a protective layer by the action of a reagent especially hexamethyldisilazane which permits trialkylsilylation. The layer prevents aging of the oxide layer even over several months storage. Before subsequent processing steps, the protective layer can easily be removed again by thermal oxidation, without forming interfering by-products.

Abstract: A method for crucible-free zone pulling of silicon monocrystalline rods is described. According to the invention, a polycrystalline silicon rod obtained by crucible pulling according to the Czochralski procedure is used in lieu of the polycrystalline silicon rod produced by vapor deposition.

Abstract: A process for polishing silicon wafers includes the step of carrying out last polishing step in the polishing operation in such a way that a protective film of silicon dioxide is produced on the surface of the polished wafer. The film does not interfere with e.g., the subsequent oxidation processes. The protective film protects the wafer surface from the many effects arising in subsequent processes which may unfavorably influence the quality of the surface.

Abstract: Point defects or impurities, which are detrimental to the quality of elecnic components, can be eliminated by means of rearsurface damage, which induces dislocations and/or stacking faults, by means of mechanical stress to the semiconductor wafers used in the manufacture of those components. For this purpose, the semiconductor wafers are brought into contact, before polishing, oxidation and thermal treatment, with moving carrier bodies covered with an elastic carrier medium having abrasive grain bonded to it, which creates the desired mechanical stress by forming a large number of very fine scratches and fissures in the surface of the semiconductor wafers.

Abstract: The inert or oxidizing auxiliary gases used in the manufacture of optical waveguides often contain traces of water which can be the cause of disruptive OH groups in the glass fiber. According to the invention, this disruption is overcome by reducing the hydroxyl content of optical waveguides by treating the auxiliary gases with heavy water (D.sub.2 O), so as to replace the hydrogen atom in the OH groups with deuterium, and then subjecting the gases to a drying step. Preferably, the auxiliary gases are subjected to a preliminary drying prior to treatment with D.sub.2 O.

Abstract: A method is described according to which articles of quartz glass, particrly quartz crucibles for use in crucible pulling according to Czochralski of high-purity synthetic quartz glass can be produced. High-purity silicon tetrachloride is hydrolized with water. The hydrolysis product is separated, dried, shaped, sintered and superficially fused.

Abstract: A process for the chemical vapor deposition of oxidic particles by oxidat of halides or halide mixtures wherein dinitrogen monoxide is used as the oxidizing agent. The reaction is carried out at comparatively low temperatures of between 900.degree. and 1150.degree. C., but results in high yields.

Abstract: For the manufacture of semiconductor wafers with a rear side having a geting action in subsequent oxidation processes by means of the action of light, especially laser, radiation ("laser damage"), there are advantageously chosen wafers with a fine surface structure that contains faces that are inclined by at least 15.degree. in the actual profile by comparison with the geometrically ideal profile of the surface according to known standards. As a result, in comparison to smooth surfaces, considerable savings in energy and time are achieved.

Abstract: A device is provided for treating gases or mixtures of gases at high temptures, such as, for example, for the reaction, known as tetraconversion, of silicon tetrachloride with hydrogen to form trichlorosilane. The device has a heat-insulated housing having gas-inlet and gas-outlet openings and a plurality of resistance heaters disposed in the housing that are directly electrically heated and around or through which the gases to be treated flow. According to a preferred embodiment, the device is also provided with an integrated heat-exchanger unit.

Abstract: A process for the removal of carbon- and iron-containing impurities from icon fragments which result when polycrystalline formed silicon bodies produced by vapor phase deposition undergo a crushing treatment. The removal is effected by several steps comprising nitrate treatment, annealing, acid and magnetic treatment, leaving the treated fragments in a state of highest purity that makes them particularly useful in the crucible-pulling process of Czochralski.

Abstract: A method for producing contrast rich, permanent and slag-free characterizations, particularly on polished semiconductor disks is described, in which the surface for generating the surface pattern is partially melted by laser radiation. According to the invention, a surface segment corresponding to 1.5 to 6.5 times the surface area of the desired surface pattern is irradiated, and the semiconductor material is caused to melt and partially vaporize only in the center thereof.

Abstract: Waste gases resulting from the production of silicon in connection with the ormation or decomposition of chlorosilanes, which gases always contain hydrogen chloride, can be worked up without removal of the hydrogen chloride. For this purpose, the waste gases which, after separation from the chlorosilanes, only contain hydrogen and hydrogen chloride, are subjected to combustion with addition of air and, after addition of silicon tetrachloride, the result being highly dispersed SiO.sub.2. The hydrogen chloride then remaining in the gaseous phase is returned to the process stream for production of trichlorosilane.