Abstract: Thin semiconductor wafers and components manufactured therefrom, for instance solar cells of crystalline silicon, are subject to an increased breakage risk because of the brittle nature of the material and require a minimum thickness for the wafer in order to assure reliable handling. For improving the handling, a semiconductor wafer is provided surface-wide with a mechanical protective layer and this semiconductor wafer is subsequently subjected to a shaping treatment.

Abstract: The present invention provides a heterogeneous catalyst based on silicon dioxide, as well as, a method for manufacturing same. The catalyst of the present invention is constructed from a porous material produced from large-surface glass bodies containing catalytically active additives by leaching with mineral acid and the additives are incorporated into the network of the glass body in the form of metal oxides insoluble in hot mineral acid. The catalyst exhibits a high active surface and is universally employable because it contains only a slight amount of undesired impurities, is highly reactive, and has a high structural stability up to about 1000.degree. C.

Abstract: The invention concerns a process for the manufacture of substrates from carbon-coated SiO.sub.2 fabric that can be used for large-surface silicon bodies, in which mineral materials or waste containing SiO.sub.2 are used as starting materials and a mixture of Al.sub.2 O.sub.3 and oxides of the alkaline and/or alkaline earth metals is used as a flux for the transformation into the glass phase. The glass fibers made from the homogenous glass melt are processed into a glass fabric, which is then subjected to an acid leaching process and coated with carbon. The process is used for the low-cost production of substrates for silicon bodies that are manufactured according to the strip-coating process for use in solar cells.

Abstract: Highly purified starting materials for the production of silicon suitable for fabrication of solar cells are produced via the carbo-thermal reduction process. A carbon-containing material with impurities therein, either by itself or admixed with glass bodies, which are attained from a melt of quartz sand and glass-forming additives formed into a fiber form and pulverized, is converted into a granulate form with the aid of a bonding agent. The resultant granulates are contacted with a hot inorganic acid, such as 3N HCl at about 90.degree. C., to extract substantially all impurities from the granulates, which can be in pellet or tablet form. The resultant purified pellets are then directly charged into an electrical arc furnace to yield solar-quality silicon. With this process, highly purified SiO.sub.2 and highly purified carbon are produced in a simple and cheap manner. The impurity level for boron, phosphorus and transition metal in these starting materials is less than about 10 ppm.

Abstract: A method for manufacturing distributor and mixer elements for optical communications technology, which elements have at least two glass fiber light waveguides fused to one another along a given segment, characterized by the steps of forming a preform by arranging at least two fiber optical rods to extend parallel to each other, fusing the arranged rods to one another in at least one sharply limited longitudinal area, then subsequently heating the preform and drawing the elements therefrom.

Abstract: A process and apparatus for producing light conducting fibers characterized by introducing multi-component glasses into a quartz glass crucible, melting the multi-component glasses, homogenizing and refining the melt, subsequently drawing the glass fiber through an opening in the base of the quartz crystal and then coating the fiber with an optically active synthetic material. During the homogenizing and refining of the melt, gas, such as dry oxygen, is introduced and passed through the melt. So that fibers of any length can be drawn, additional glass material in the form of premanufactured, highly pure glass rods are introduced into the crucible as necessary.

Abstract: A device for drawing a plurality of cladded light conducting fibers utilizing a double crucible having an inner crucible and an outer crucible with each of the crucibles having a bottom and receiving a melt of the respective material, and having nozzle pairs with the nozzle of the inner crucible being aligned axially with the nozzle of the outer crucible, the device including a device for gathering the pulled fibers to form a bundle and for coating the pulled cladded fibers characterized by the nozzles being exclusively arranged at points on the bottoms of their respective crucibles where the same temperature prevails for the glass melt present in the double crucibles. To accomplish this, the nozzles are located between and equal distance from the parallel boundary lines of the bottom of the inner crucible so that the melt drawn through the nozzle travels the same distance in all directions.

Abstract: A method and apparatus for producing a light conducting fiber having a core disposed in a loose fitting cladding tube characterized by a double crucible arrangement having a first crucible for a melt of the material for the cladding tube and a second crucible for the melt of the material of the core. The second crucible has an orifice of a given diameter and the first crucible has a ring-shaped orifice with an inner diameter greater than the given diameter of the orifice of the second crucible with the center of the ring-shaped orifice being arranged substantially on a central axis of the orifice of the second crucible so that a core drawn from the orifice of the second crucible is substantially concentrically disposed within the tube of material drawn from the ring-shaped orifice.