Shin-Etsu Chemical Co., Ltd.

Fumitaka Kume

Shigeyoshi Netsu

Kyoji Oguro

Takaaki Shimizu

Junichi Okada

Yasushi Kurosawa

Shinichi Kurotani

Masaru Hirahara

Kouichi Kobayashi

A clean and high-purity polycrystalline silicon mass having a small content of chromium, iron, nickel, copper, and cobalt in total, which are heavy metal impurities that reduce the quality of single-crystal silicon, can be obtained from a silicon rod by before crushing a polycrystalline silicon rod, removing at least 70 mm of a polycrystalline silicon portion from the electrode side end of the polycrystalline silicon rod extracted to the outside of a reactor is provided. Thereby, the polycrystalline silicon portion in which the total of the chromium, iron, nickel, copper, and cobalt concentrations in a bulk is not less than 150 ppta can be removed.

Process for producing polycrystalline silicon mass

The present invention provides a technique by which heat can be efficiently recovered from a coolant used to cool a reactor, and contamination with dopant impurities from an inner wall of a reactor when polycrystalline silicon is deposited within the reactor can be reduced to produce high-purity polycrystalline silicon. With the use of hot waterhaving a temperature higher than a standard boiling point as a coolant fed to the reactor, the temperature of the reactor inner wall is kept at a temperature of not more than 370&#xb0; C. Additionally, the pressure of the hot waterto be recovered is reduced by a pressure control section provided in a coolant tankto generate steam. Thereby, a part of the hot water is taken out as steam to the outside, and reused as a heating source for another application.

System for producing polycrystalline silicon, apparatus for producing polycrystalline silicon, and process for producing polycrystalline silicon

The upper electrodehas a holeextending from an upper surfaceto a lower surface, a boltis inserted from the upper surfaceof the upper electrodeinto the hole, and secured in a lower electrodeby a screw. A gapbetween an inside of the holeand a straight body portion of the boltallows the upper electrodeto slide in all directions in a placement surface (upper surface of the lower electrodein contact with the lower surfaceof the upper electrodein FIG.) that is a contact surface with an upper surface of the lower electrode, thereby providing an effect of preventing occurrence of a crack or a break in a U rod that can be expanded and contracted in all directions during a vapor phase growth process.

Carbon electrode with slidable contact surfaces and apparatus for manufacturing polycrystalline silicon rod

An inner wallof a reactorhas a two-layer structure: an anticorrosive layercomprising an alloy material having high anticorrosiveness is provided on the inner side of the reactor contacting a corrosive process gas, and a heat conductive layerfor efficiently conducting the heat within the reactorfrom an inner wall surface to a coolant flow passageis provided on the outer side of the reactor (outer-wall side). The anticorrosive layercomprises an alloy material having a composition for which a value R, defined by R=[Cr]+[Ni]&#x2212;1.5 [Si], is not less than 40% wherein [Cr] is a mass content (% by mass) of chromium (Cr), [Ni] is a mass content (% by mass) of nickel (Ni), and [Si] is a mass content (% by mass) of silicon (Si).

Reactor for producing polycrystalline silicon, system for producing polycrystalline silicon, and process for producing polycrystalline silicon

The present invention provides a technique by which heat can be efficiently recovered from a coolant used to cool a reactor, and contamination with dopant impurities from an inner wall of a reactor when polycrystalline silicon is deposited within the reactor can be reduced to produce high-purity polycrystalline silicon. With the use of hot waterhaving a temperature higher than a standard boiling point as a coolant fed to the reactorthe temperature of the reactor inner wall is kept at a temperature of not more than 370&#xb0; C. Additionally, the pressure of the hot waterto be recovered is reduced by a pressure control section provided in a coolant tankto generate steam. Thereby, a part of the hot water is taken out as steam to the outside, and reused as a heating source for another application.

The length of the polycrystalline silicon rod () is measured with a tape measure, then the polycrystalline silicon rod () is hit with a hammer (), and this hammering sound is recorded in a recorder () through a microphone (). Then, an acoustic signal of the hammering sound is subjected to a fast Fourier transform and a frequency distribution is displayed. Furthermore, a peak frequency f is detected which shows the largest sound volume in the frequency distribution obtained after the fast Fourier transform. The relationship between the length (L) of the polycrystalline silicon rod and the peak frequency f is obtained, and the firmness of the polycrystalline silicon rod is determined on the basis of whether or not the peak frequency f is in a range of f&#x2267;1,471/L (region A).

Polycrystalline silicon rod and method for manufacturing polycrystalline silicon rod

The present invention provides a method for making it possible to easily and simply measure approximate concentration of substitutional carbon impurities in a desired position in a polycrystalline silicon rod. A polycrystalline silicon plate is sliced out from a polycrystalline silicon rod and both surfaces of the polycrystalline silicon plate are mirror-polished to reduce the polycrystalline silicon plate to thickness of 2.12&#xb1;0.01 mm. A calibration curve is created according to an infrared absorption spectroscopy and on the basis of a standard measurement method using a single crystal silicon standard sample having known substitutional carbon concentration and thickness of 2.00&#xb1;0.01 mm, an infrared absorption spectrum in a frequency domain including an absorption zone peak of substitutional carbon of the polycrystalline silicon plate after the mirror polishing is calculated under conditions same as conditions during the calibration curve creation, and substitutional carbon concentration is calculated without performing thickness correction.

Method for measuring carbon concentration in polycrystalline silicon

One end side of a core wire holderis formed into a shape of a truncated cone and has an inclined surface. In the end portion, an openingis provided, and a hollow portionis formed, a silicon core wirebeing inserted into the hollow portionand held therein. On the surface of the silicon core wire, polycrystalline siliconis vapor deposited by the Siemens method to produce a polycrystalline silicon rod. On the inclined surface of the truncated cone portion in the vicinity of the opening, as a thermal insulating layer, annular slitstoare formed from an outer circumferential surface in the vicinity of the opening toward the hollow portion. The annular slit acts as a thermal insulating portion, and suppresses escape of the heat to heat the one end side of the core wire holder

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Niigata, Japan

Fumitaka Kume