A method for producing a polycrystalline silicon processed article includes removing a polycrystalline silicon rod, obtained by precipitating polycrystalline silicon on a silicon core wire held by a carbon member connected to an electrode in a reactor by the Siemens method, in a state in which the carbon member is included at the end portion thereof and processing the polycrystalline silicon rod. The polycrystalline silicon rod is detached from the electrode and the carbon member present on the end portion of the polycrystalline silicon rod is covered using a covering material until the processing, whereby the polycrystalline silicon rod and the carbon member are handled in a separated state.

An integrated sleeve structure is provided between an electrode configured to feed power to a silicon core wire and a bottom plate part. Sealing members are arranged on at least part of a flange part of an insulating member and on at least part of a straight part of the insulating member.

A silicon-carbon composite powder having Si and C distributed throughout each particle is provided. The weight ratio of carbon to silicon on the surface of a particle (C/Si).sub.surface is greater than the weight ratio of carbon to silicon within the total particle (C/Si).sub.total. The silicon-carbon composite powder is produced by simultaneously feeding into a reactor a gaseous stream of a SiH.sub.4, Si.sub.2H.sub.6, Si.sub.3H.sub.8 and/or organosilane and a gaseous stream of at least one hydrocarbon of ethylene, ethane, propane and acetylene and reacting the streams using plasma enhanced chemical vapor deposition.

A silicon-carbon composite powder having Si and C distributed throughout each particle is provided. The weight ratio of carbon to silicon on the surface of a particle (C/Si).sub.surface is greater than the weight ratio of carbon to silicon within the total particle (C/Si).sub.total. The silicon-carbon composite powder is produced by simultaneously feeding into a reactor a gaseous stream of a SiH.sub.4, Si.sub.2H.sub.6, Si.sub.3H.sub.8 and/or organosilane and a gaseous stream of at least one hydrocarbon of ethylene, ethane, propane and acetylene and reacting the streams using plasma enhanced chemical vapor deposition.

The present invention provides a polycrystalline silicon rod whose rod surface portion has a phosphorus concentration of 0.015 ppba or less, in which the ratio (P2/P1) of the phosphorus concentration (P2) of the rod center portion to the phosphorus concentration (P1) of the rod surface portion is within the range of 2 or lower. The present invention also provides a method for producing a polycrystalline silicon rod by the Siemens method that assembles a polycrystalline silicon seed rod in a reactor, then heats the seed rod up to a temperature of 1000° C. or more and less than the melting point of silicon by energization heating, and supplies a raw material gas including trichlorosilane gas and hydrogen gas as the main components to the reactor at the heating temperature to deposit and grow silicon on the seed rod surface.

The present invention provides a polycrystalline silicon rod whose rod surface portion has a phosphorus concentration of 0.015 ppba or less, in which the ratio (P2/P1) of the phosphorus concentration (P2) of the rod center portion to the phosphorus concentration (P1) of the rod surface portion is within the range of 2 or lower. The present invention also provides a method for producing a polycrystalline silicon rod by the Siemens method that assembles a polycrystalline silicon seed rod in a reactor, then heats the seed rod up to a temperature of 1000° C. or more and less than the melting point of silicon by energization heating, and supplies a raw material gas including trichlorosilane gas and hydrogen gas as the main components to the reactor at the heating temperature to deposit and grow silicon on the seed rod surface.

According to the present invention, a resin material that has the following surface concentration of impurities is consistently used in production of polycrystalline silicon. Values obtained from quantitative analysis by ICP-mass spectrometry using a 1 wt % nitric acid aqueous solution as an extraction liquid are: a phosphorous (P) concentration of 50 pptw or less; an arsenic (As) concentration of 2 pptw or less; a boron (B) concentration of 20 pptw or less; an aluminum (Al) concentration of 10 pptw or less; a total concentration of 6 elements of iron (Fe), chromium (Cr), nickel (Ni), copper (Cu), sodium (Na), and zinc (Zn) of 80 pptw or less; a total concentration of 10 elements of lithium (Li), potassium (K), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), molybdenum (Mo), tin (Sn), tungsten (W), and lead (Pb) of 100 pptw or less.

According to the present invention, a resin material that has the following surface concentration of impurities is consistently used in production of polycrystalline silicon. Values obtained from quantitative analysis by ICP-mass spectrometry using a 1 wt % nitric acid aqueous solution as an extraction liquid are: a phosphorous (P) concentration of 50 pptw or less; an arsenic (As) concentration of 2 pptw or less; a boron (B) concentration of 20 pptw or less; an aluminum (Al) concentration of 10 pptw or less; a total concentration of 6 elements of iron (Fe), chromium (Cr), nickel (Ni), copper (Cu), sodium (Na), and zinc (Zn) of 80 pptw or less; a total concentration of 10 elements of lithium (Li), potassium (K), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), molybdenum (Mo), tin (Sn), tungsten (W), and lead (Pb) of 100 pptw or less.

Polycrystalline silicon is produced in a chemical vapour deposition reactor, wherein, outside the reactor at at least one position on at least one reactor component, vibrations of the reactor are measured using a measurement device and optionally recorded. The vibrations may be used to identify rod fall over and other events occurring within the reactor.

For evaluating a polycrystalline silicon rod to be used as a raw material for production of FZ Si single crystals, novel evaluation values (values of characteristics×amount of crystals) including the amount of crystals grown in the growth direction (radial direction) are defined and the homogeneity in crystal characteristics in the growth direction (radial direction) is evaluated. Specifically, the homogeneity of the polycrystalline rod is evaluated by sampling a plurality of specimen plates each having, as a principal plane thereof, a cross-section perpendicular to a radial direction of the polycrystalline rod grown by a Siemens method at equal intervals in the radial direction, determining values of characteristics of the crystals of the specimen plates by measurements, and by using evaluation values obtained by multiplying amounts of the crystals (relative amounts of the crystals) at sites where the specimen plates have been sampled by the values of the crystal characteristics.