Abstract: A cylindrical vessel made of carbon is used in the production of silicon. The inner surface of the vessel comes into contact with a silicon melt, wherein the permeation with silicon melt is reduced, formation of SiC is suppressed, and the vessel is resistant to deformation even when volumetric expansion ascribable to silicon is brought about. The carbon-made cylindrical vessel is made of a carbon material having a bulk specific gravity of 1.8 or more. The thermal expansion coefficient of the carbon material at 350 to 450° C. is preferably 3.5×10?6/° C. to 6.0×10?6/° C. A process for producing silicon uses said vessel wherein a chlorosilane is reacted with hydrogen.

Abstract: It is an object to provide a reaction apparatus of the chlorosilanes sufficiently capable of suppressing that a raw gas such as the chlorosilanes supplied into the reaction vessel penetrates a pipe wall of the reaction vessel to leak externally. In a reaction apparatus of the chlorosilanes for heating a reaction portion that is a section from the bottom end portion to a specified height in the carbon reaction vessel and that has an inside face to which silicon has deposited, and for reacting the chlorosilanes by making the chlorosilanes and hydrogen to come into contact with the inside face of the reaction portion, a gas penetration preventing processing for preventing the chlorosilanes supplied to the reaction vessel from penetrating a pipe wall of the non reaction portion in the reaction vessel is carried out to the inside face and/or the outside face of the non reaction portion on the side upper than the reaction portion in the reaction vessel.

Abstract: There is provided a reaction vessel whereby silicon produced can be smoothly recovered dropwise without excessive thermal load on constitutional parts of the reaction vessel, a silicon deposition feedstock gas can be reacted efficiently even when the reaction vessel is scaled up to industrial large-scale equipment, generation of silicon fine powder and silane oligomers can be suppressed, and industrial silicon production can be performed over extended periods. The tubular reaction vessel comprises a longitudinally-extending wall with a space thereinside, wherein a silicon deposition feedstock gas inflow opening and a deposited silicon discharge opening are provided at an upper portion and a lower end portion respectively, and a flow resistance-increasing region is created on a wall surface of the tubular reaction vessel that is contacted with a feedstock gas. The flow resistance-increasing region is at least one of protrudent, concave and sloped regions.

Abstract: There is provided a production process of silicon that can reutilize a receiving vessel without breaking of the receiving vessel and does not cause inclusion of impurities in silicon from the receiving vessel in contact with molten silicon. The production process of silicon comprises the steps of: depositing silicon in a solid state or molten state by contacting gas mixture of hydrogen and silanes to the surface having the temperature range of 600 to 1700° C.; melting a part or the whole of the deposited silicon, dropping the melt from a deposition surface, and receiving the dropped molten silicon in a receiving vessel, wherein said receiving vessel comprises a silicon bottom plate member(s) and a plurality of silicon side plate members that are installed upright direction from the peripheral part of the bottom plate member.

Abstract: A silicon production reactor comprising a reaction vessel and heating means, said reaction vessel comprising a vertically extending wall and a space surrounded by the wall, said heating means being capable of heating at least a part, including lower end portion, of the wall's surface facing the space to a temperature of not lower than the melting point of silicon, said silicon production reactor being adapted to flow raw gas for silicon deposition from an upper part of the space of the reaction vessel toward a lower part thereof, characterized in that the space of the reaction vessel is of slit form in cross-sectional view. This silicon production reactor is capable of attaining improvement with respect to problems encountered at apparatus scaleup, such as decrease of reactivity of raw gas and generation of by-products, thereby accomplishing a striking enhancement of production efficiency.

Abstract: A silicon production process which improves the production efficiency of trichlorosilane while an industrially advantageous output is ensured and the amount of the by-produced tetrachlorosilane is suppressed. This process does not require a bulky reduction apparatus for the by-produced tetrachlorosilane, can construct a closed system, which is a self-supporting silicon production process, can easily control the amount of the by-produced tetrachlorosilane and therefore can adjust the amount of tetrachlorosilane to be supplied to a tetrachlorosilane treating system when the tetrachlorosilane treating system is used. This process comprises a silicon deposition step for forming silicon by reacting trichlorosilane with hydrogen at a temperature of 1,300° C.

Abstract: Foamed polycrystalline silicon having bubbles therein and an apparent density of 2.20 g/cm3 or less. This silicon generates an extremely small amount of fine grains by crushing and can be easily crushed. There is also provided a method of producing foamed polycrystalline silicon. There is further provided a polycrystalline silicon production apparatus in which the deposition and melting of silicon are carried out on the inner surface of a cylindrical vessel, a chlorosilane feed pipe is inserted into the cylindrical vessel to a silicon molten liquid, and seal gas is supplied into a space between the cylindrical vessel and the chlorosilane feed pipe.

Abstract: A production method of silicon which comprises the steps of bringing a silane into contact with a surface of a substrate so as to cause silicon to be deposited while the surface of the substrate is heated to and kept at a temperature lower than the melting point of the silicon, and raising the temperature of the surface of the substrate so as to cause a portion or all of the deposited silicon to melt and drop from the surface of the substrate and be recovered.

Abstract: A silicon production process which improves the production efficiency of trichlorosilane while an industrially advantageous output is ensured and the amount of the by-produced tetrachlorosilane is suppressed. This process does not require a bulky reduction apparatus for the by-produced tetrachlorosilane, can construct a closed system, which is a self-supporting silicon production process, can easily control the amount of the by-produced tetrachlorosilane and therefore can adjust the amount of tetrachlorosilane to be supplied to a tetrachlorosilane treating system when the tetrachlorosilane treating system is used.

Abstract: A production method of silicon which comprises the steps of bringing a silane into contact with a surface of a substrate so as to cause silicon to be deposited while the surface of the substrate is heated to and kept at a temperature lower than the melting point of the silicon, and raising the temperature of the surface of the substrate so as to cause a portion or all of the deposited silicon to melt and drop from the surface of the substrate and be recovered.

Abstract: Foamed polycrystalline silicon having bubbles therein and an apparent density of 2.20 g/cm3 or less. This silicon generates an extremely small amount of fine grains by crushing and can be easily crushed. There is also provided a method of producing foamed polycrystalline silicon. There is further provided a polycrystalline silicon production apparatus in which the deposition and melting of silicon are carried out on the inner surface of a cylindrical vessel, a chlorosilane feed pipe is inserted into the cylindrical vessel to a silicon molten liquid, and seal gas is supplied into a space between the cylindrical vessel and the chlorosilane feed pipe.