Shin-Etsu Film Co., Ltd

Sunric Co., Ltd

Tatsuhiko Hongu

Yasuhiro Kato

Hiroshi Hagimoto

Tomishi Kimura

Kenichi Uesaka

Provided is a method for the preparation of polycrystalline silicon in which, in conducting preparation of polycrystalline silicon by the Siemens method or by the monosilane method, no outer heating means is necessitated for the core member (seed rod), onto which polycrystalline silicon is deposited, from the initial stage of heating, the deposition rate is high and the core member seed rod can be used repeatedly. The method for deposition of high-purity polycrystalline silicon, at a high temperature, onto a white-heated seed rod in a closed reaction furnace by pyrolysis or hydrogen reduction of a starting silane gas supplied thereto, is characterized in that the seed rod is a member made from an alloy having a recrystallization temperature of 1200&#xb0; C. or higher. It is preferable that the alloy member is of an alloy of Re&#x2014;W, W&#x2014;Ta, Zr&#x2014;Nb, titanium-zirconium, or a carbon-added molybdenum (TZM) in the form of a wire member having a diameter of at least 0.5 mm, a plate member having a thickness of at least 1 mm or a prismatic member, or a tubular member having a diameter of at least 1 mm, wall thickness of at least 0.2 mm with an inner diameter not exceeding 5 mm, that the plate member, wire member, prismatic member or tubular member has a tapered form and further that the tubular member is a tapered duplex tube.

Method for manufacturing polycrystalline silicon, and polycrystalline silicon for solar cells manufactured by the method

Different from conventional so-called mix-type film capacitors involving several disadvantages, in which the dielectric layers consist of a combination of a dielectric plastic resin film and an insulating paper sheet, the invention provides an all-film oil-impregnated capacitor in which the dielectric layers consist only of a plastic resin film such as a biaxially oriented polypropylene resin film (OPP film) suitable for use in microwave ovens. The all-film capacitor of the invention can be obtained and has satisfactory properties only when prepared by using specified materials including the OPP film, aluminum foil and capacitor oil and under specified conditions relative to the dielectric tangent values and dielectric capacity values before and after impregnation with a capacitor oil as well as the conditions in the step of oil impregnation.

Oil-impregnated film capacitor and preparation method thereof

Disclosed is an efficient and inexpensive method for the purification of low-grade silicon such as metallurgical-grade metallic silicon to give solar cell-grade silicon. The method comprises: (a) melting the starting low-grade silicon in a melting crucible; (b) bringing an end of an elongated linear fiber compact body of a refractory material, e.g., bundles of carbon fibers, into contact with the molten silicon in the crucible so that the molten silicon infiltrates and migrates through the fiber compact body by the capillary phenomenon to reach the other end of the fiber compact body held at a lower level than the first end; and (c) receiving the effluent of molten silicon discharged out of the second end of the fiber compact body in a receptacle crucible. The atmospheric gas is preferably a gaseous mixture of an inert gas, e.g., argon, and a small amount of a reactive gas, e.g., oxygen and hydrogen chloride, which reacts with the impurity elements such as boron and phosphorus in the starting low-grade silicon material to form a more volatilizable compound of the impurity element.

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Tokyo, Japan

Tatsuhiko Hongu