Abstract: The invention provides chunk polycrystalline silicon having a concentration of carbon at the surface of 0.5-35 ppbw. A process for cleaning polycrystalline silicon chunks having carbon contaminations at the surface, includes a thermal treatment of the polycrystalline silicon chunks in a reactor at a temperature of 350 to 600° C., the polycrystalline silicon chunks being present in an inert gas atmosphere during the thermal treatment, and the polycrystalline silicon chunks after the thermal treatment having a concentration of carbon at the surface of 0.5-35 ppbw.

Abstract: The content of phosphorus in polycrystalline silicon prepared by the Siemens process is reduced by treating phosphorus-containing steel surfaces with an ?-amino-functional alkoxysilane. The treated surface exhibits less corrosion in an atmosphere of moist hydrogen chloride, and less loss of phosphorus as a result.

Abstract: A rod having a length of 0.5 m to 4 m and having a diameter of 25 mm to 220 mm, comprising a high-purity alloy composed of 0.1 to 50 mol % germanium and 99.9 to 50 mol % silicon, the alloy having been deposited on a thin silicon rod or on a thin germanium-alloyed silicon rod, the deposited alloy having a polycrystalline structure.

Abstract: The invention provides chunk polycrystalline silicon having a concentration of carbon at the surface of 0.5-35 ppbw. A process for cleaning polycrystalline silicon chunks having carbon contaminations at the surface, includes a thermal treatment of the polycrystalline silicon chunks in a reactor at a temperature of 350 to 600° C., the polycrystalline silicon chunks being present in an inert gas atmosphere during the thermal treatment, and the polycrystalline silicon chunks after the thermal treatment having a concentration of carbon at the surface of 0.5-35 ppbw.

Abstract: The present invention relates to polycrystalline silicon chunks which are cubic and have a metal content of less than 200 pptw and a dopant content of less than 50 ppta. Methods for producing polycrystalline silicon chunks, include the steps of providing a polycrystalline silicon rod, comminuting the polycrystalline silicon rod into cubic chunks, and cleaning the polycrystalline silicon chunks, wherein comminution takes place using a spiked-roll crusher having at least one spiked roll, the spiked roll including W2C phases or WC phases with 0.1-10% of a metal carbide selected from the group consisting of titanium carbide, chromium carbide, molybdenum carbide, vanadium carbide, and nickel carbide or consisting of steel with 1-25% W.

Abstract: The invention provides chunk polycrystalline silicon having a concentration of carbon at the surface of 0.5-35 ppbw. A process for cleaning polycrystalline silicon chunks having carbon contaminations at the surface, includes a thermal treatment of the polycrystalline silicon chunks in a reactor at a temperature of 350 to 600° C., the polycrystalline silicon chunks being present in an inert gas atmosphere during the thermal treatment, and the polycrystalline silicon chunks after the thermal treatment having a concentration of carbon at the surface of 0.5-35 ppbw.

Abstract: The invention relates to a polycrystalline silicon portion having at least one fracture surface or cut surface, which includes metal contamination of from 0.07 ng/cm2 to 1 ng/cm2. The invention also relates to a method for breaking a silicon body, preferably a rod of polycrystalline silicon, including the steps: a) determining the lowest natural bending frequency of the silicon body; b) exciting the silicon body in its lowest natural bending frequency by means of an oscillation generator, the excitation being carried out at an excitation point of the silicon body such that the silicon body breaks at the excitation point; so that a silicon portion having a fracture surface results which includes metal contamination of from 0.07 ng/cm2 to 1 ng/cm2.

Abstract: The content of phosphorus in polycrystalline silicon prepared by the Siemens process is reduced by treating phosphorus-containing steel surfaces with an ?-amino-functional alkoxysilane. The treated surface exhibits less corrosion in an atmosphere of moist hydrogen chloride, and less loss of phosphorus as a result.

Abstract: The present invention relates to polycrystalline silicon chunks which are cubic and have a metal content of less than 200 pptw and a dopant content of less than 50 ppta. Methods for producing polycrystalline silicon chunks, include the steps of providing a polycrystalline silicon rod, comminuting the polycrystalline silicon rod into cubic chunks, and cleaning the polycrystalline silicon chunks, wherein comminution takes place using a spiked-roll crusher having at least one spiked roll, the spiked roll including W2C phases or WC phases with 0.1-10% of a metal carbide selected from the group consisting of titanium carbide, chromium carbide, molybdenum carbide, vanadium carbide, and nickel carbide or consisting of steel with 1-25% W.

Abstract: Trichlorosilane production is increased while simultaneously lowering environmental burden due to destruction and disposition of high boilers by feeding high boilers from trichlorosilane production or from polycrystalline silicon production into a fluidized bed for production of trichlorosilane from metallic silicon and hydrogen chloride.

Abstract: The invention relates to a method for producing polycrystalline silicon rods by deposition of silicon on at least one thin rod in a reactor, wherein, before the silicon deposition, hydrogen halide at a temperature of 400-1000° C. is introduced into the reactor containing at least one thin rod and is irradiated by means of UV light, as a result of which halogen and hydrogen radicals arise and the volatile halides that form are removed from the reactor.

Abstract: A rod having a length of 0.5 m to 4 m and having a diameter of 25 mm to 220 mm, comprising a high-purity alloy composed of 0.1 to 50 mol % germanium and 99.9 to 50 mol % silicon, the alloy having been deposited on a thin silicon rod or on a thin germanium-alloyed silicon rod, the deposited alloy having a polycrystalline structure.

Abstract: The disclosure relates to an apparatus and a method for producing a single crystal of semiconductor material. The apparatus comprises a chamber and a crucible which is arranged in the chamber and is enclosed by a crucible heater, a radiation shield for shielding a growing single crystal and thermal insulation between the crucible heater and an inner wall of the chamber. The apparatus may include a resilient seal which seals a gap between the inner wall and the thermal insulation and forms an obstacle for the transport of gaseous iron carbonyls to the single crystal. The disclosure also relates to a method for producing a single crystal of semiconductor material by using the apparatus, the single crystal which is produced and a semiconductor wafer cut therefrom.

Abstract: Trichlorosilane production is increased while simultaneously lowering environmental burden due to destruction and disposition of high boilers by feeding high boilers from trichlorosilane production or from polycrystalline silicon production into a fluidized bed for production of trichlorosilane from metallic silicon and hydrogen chloride.

Abstract: The disclosure relates to an apparatus and a method for producing a single crystal of semiconductor material. The apparatus comprises a chamber and a crucible which is arranged in the chamber and is enclosed by a crucible heater, a radiation shield for shielding a growing single crystal and thermal insulation between the crucible heater and an inner wall of the chamber. The apparatus may include a resilient seal which seals a gap between the inner wall and the thermal insulation and forms an obstacle for the transport of gaseous iron carbonyls to the single crystal. The disclosure also relates to a method for producing a single crystal of semiconductor material by using the apparatus, the single crystal which is produced and a semiconductor wafer cut therefrom.

Abstract: A process is for producing a semiconductor wafer with a front surface and a back surface, in which the semiconductor wafer is subjected to two-sided polishing. The process includes the following: (a) producing a hydrophobic surface on the semiconductor wafer by treating the semiconductor wafer with an aqueous HF solution; (b) simultaneous polishing of the front surface and the back surface of the semiconductor wafer with a surface which has been rendered hydrophobic, with an alkaline polishing abrasive being continuously supplied between two rotating upper and lower polishing plates, which are both covered with a polishing cloth, the pH of the polishing abrasive being from pH 8.5 to pH 12.5; (c) after an intended polishing abrasion has been reached, supplying a stopping agent to the semiconductor wafer; and (d) removing the semiconductor wafer from the polishing plates.

Abstract: A process is for producing a semiconductor wafer with a front surface and a back surface, in which the semiconductor wafer is subjected to two-sided polishing. The process includes the following: (a) producing a hydrophobic surface on the semiconductor wafer by treating the semiconductor wafer with an aqueous HF solution; (b) simultaneous polishing of the front surface and the back surface of the semiconductor wafer with a surface which has been rendered hydrophobic, with an alkaline polishing abrasive being continuously supplied between two rotating upper and lower polishing plates, which are both covered with a polishing cloth, the pH of the polishing abrasive being from pH 8.5 to pH 12.5; (c) after an intended polishing abrasion has been reached, supplying a stopping agent to the semiconductor wafer; and (d) removing the semiconductor wafer from the polishing plates.

Abstract: A method is provided to remove crystal regions from silicon wafers which are damaged as a consequence of mechanical machining of the silicon wafers. The silicon wafers are pretreated with an aqueous solution containing hydrogen fluoride. Then the wafers are etched in an aqueous solution exposed to ultrasound and containing alkali metal hydroxide at temperatures from 55.degree. C. to 95.degree. C.

Abstract: A process for producing silicon wafers which have a storage-stable surface and which can be thermally oxidized directly, that is to say, without a prior HF immersion bath, and without the addition of halogen-containing gases, it being possible to achieve an equal or better oxidation result than that achieved by including these measures.

Abstract: Silicon wafers are first subjected to an oxidative treatment and subsequey to exposure to organosilicon compounds which contain at least one radical in the molecule which is hydrolyzably bound to the silicon and at least one radical in the molecule having hydrophilic properties. Depending on the compound selected, more or less strongly hydrophilic or hydrophobic properties of the silicon surface can consequently be established under mild conditions. The wafers treated in such a manner have a high storage stability and retain their surface nature even under difficult climatic circumstances. The surface nature present after the oxidative treatment can then be restored particularly easily by hydrolysis.