Contamination of fluidized bed-produced polycrystalline granules by phosphorus is reduced by employing as seals and/or packings, graphite containing <500 ppmw of phosphorus.

Contamination of fluidized bed-produced polycrystalline granules by phosphorus is reduced by employing as seals and/or packings, graphite containing <500 ppmw of phosphorus.

According to the present invention, there is provided a polysilicon production apparatus including: a horizontal reaction tube having an inlet port through which gaseous raw materials including reactant gases and a reducing gas are supplied, an outlet port through which residual gases exit, a reaction surface with which the gaseous raw materials come into contact, and bottom openings through which molten polysilicon produced by the reactions of the gaseous raw materials is discharged; and first heating means adapted to heat the reaction surface of the horizontal reaction tube. The horizontal reaction tube includes reaction regions consisting of first reaction regions where polysilicon is deposited and second reaction regions where reaction by-products are converted to the reactant gases. The first reaction regions are connected in series with the second reaction regions. Also provided is a polysilicon production method using the polysilicon production apparatus.

According to the present invention, there is provided a polysilicon production apparatus including: a horizontal reaction tube having an inlet port through which gaseous raw materials including reactant gases and a reducing gas are supplied, an outlet port through which residual gases exit, a reaction surface with which the gaseous raw materials come into contact, and bottom openings through which molten polysilicon produced by the reactions of the gaseous raw materials is discharged; and first heating means adapted to heat the reaction surface of the horizontal reaction tube. The horizontal reaction tube includes reaction regions consisting of first reaction regions where polysilicon is deposited and second reaction regions where reaction by-products are converted to the reactant gases. The first reaction regions are connected in series with the second reaction regions. Also provided is a polysilicon production method using the polysilicon production apparatus.

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.

Provided is a method which not only prevents (i) accumulation of fine silicon powder in a separation device and a pipe which are provided in steps after passage of a filter and (ii) damage to a pump, but also reduces adhesion of a silane oligomer to the filter. A method, in accordance with an embodiment of the present invention, for producing polycrystalline silicon, includes: a silicon deposition step; a separation step; and a fine powder removal step of removing the fine silicon powder by passing a chlorosilane condensate through a filter.

Provided is a method which not only prevents (i) accumulation of fine silicon powder in a separation device and a pipe which are provided in steps after passage of a filter and (ii) damage to a pump, but also reduces adhesion of a silane oligomer to the filter. A method, in accordance with an embodiment of the present invention, for producing polycrystalline silicon, includes: a silicon deposition step; a separation step; and a fine powder removal step of removing the fine silicon powder by passing a chlorosilane condensate through a filter.

Provided is a polycrystalline silicon rod suitable as a raw material for production of single-crystalline silicon. A crystal piece (evaluation sample) is collected from a polycrystalline silicon rod grown by a Siemens method, and a polycrystalline silicon rod in which an area ratio of a crystal grain having a particle size of 100 nm or less is 3% or more is sorted out as the raw material for production of single-crystalline silicon. When single-crystalline silicon is grown by an FZ method using the polycrystalline silicon rod as a raw material, the occurrence of dislocation is remarkably suppressed.

Polycrystalline silicon with low contamination by impurities, especially boron and phosphorus, is manufactured by the Siemens process or by the fluidized bed process, in which deposition of polycrystalline silicon takes place in a reactor maintained within a clean room of the 1 to 100,000 class, and air entering the facility enclosing the reactors is filtered by a multiple stage filtration system wherein coarse and fine filter elements contain less than 0.1% by weight of boron and phosphorus and less than 0.01% by weight of arsenic and aluminum. Following production of the polycrystalline silicon, the polycrystalline silicon may be further treated by steps such as comminution, classifying, wet-chemical treatment, and packing, all these further steps also preferably taking place within a clean room of the 1 to 100,000 class.

Polycrystalline silicon with low contamination by impurities, especially boron and phosphorus, is manufactured by the Siemens process or by the fluidized bed process, in which deposition of polycrystalline silicon takes place in a reactor maintained within a clean room of the 1 to 100,000 class, and air entering the facility enclosing the reactors is filtered by a multiple stage filtration system wherein coarse and fine filter elements contain less than 0.1% by weight of boron and phosphorus and less than 0.01% by weight of arsenic and aluminum. Following production of the polycrystalline silicon, the polycrystalline silicon may be further treated by steps such as comminution, classifying, wet-chemical treatment, and packing, all these further steps also preferably taking place within a clean room of the 1 to 100,000 class.