Reaction furnace for producing polycrystalline silicon, apparatus for producing polycrystalline silicon, method for producing polycrystalline silicon, and polycrystalline silicon rod or polycrystalline silicon ingot

Patent metadata

Field	Value
Publication number	US-10858258-B2
Application number	US-201515501715-A
Country	US
Kind code	B2
Filing date	Jul 29, 2015
Priority date	Sep 4, 2014
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

A reaction furnace for producing a polycrystalline silicon according to the present invention is designed so as to have an in-furnace reaction space in which a reaction space cross-sectional area ratio (S=[S0−SR]/SR) satisfies 2.5 or more, which is defined by an inner cross-sectional area (So) of a reaction furnace, which is perpendicular to a straight body portion of the reaction furnace, and a total sum (SR) of cross-sectional areas of polycrystalline silicon rods that are grown by precipitation of polycrystalline silicon, in a case where a diameter of the polycrystalline silicon rod is 140 mm or more. Such a reaction furnace has a sufficient in-furnace reaction space even when the diameter of the polycrystalline silicon rod has been expanded, and accordingly an appropriate circulation of a gas in the reaction furnace is kept.

First claim

The invention claimed is:

1. A method for producing a polycrystalline silicon by a Siemens method, comprising:
reacting hydrogen with a source gas comprising one or more chlorosilane compounds to deposit polycrystalline silicon on one or more silicon core wires in a reaction furnace, thereby forming one or more polycrystalline silicon rods having a final diameter of 140 mm or more; and
during said reacting, controlling a composition ratio in wt % between trichlorosilane (TCS) and silicon tetrachloride (STC) in an exhaust gas to 1.2 or more, until a diameter of a polycrystalline silicon rod that is growing reaches 100 mmϕ;
wherein the reaction furnace has an in-furnace reaction space in which when an inner cross-sectional area of the reaction furnace, which is perpendicular to a straight body portion of the reaction furnace, is represented by S 0 , and a total sum of cross-sectional areas of polycrystalline silicon rods that are grown by precipitation of the polycrystalline silicon onto at least one pair of silicon core wires in an inverted U shape, which are arranged in the reaction furnace, is represented by S R =ΣS i ,
a reaction space cross-sectional area ratio that is defined by S=[S 0 -S R ]/S R satisfies 2.5 or more, based on the final diameter of the one or more polycrystalline silicon rods.

2. The method according to claim 1 , further comprising, during said reacting:
supplying an electric current at a high frequency between 50 Hz and 10,000 kHz to said at least one pair of silicon core wires in an inverted U shape; and
controlling a temperature within a 100 mmϕ vicinity of the core to 1400° C. or lower, until a polycrystalline silicon rod grows to a predetermined diameter.

3. The method of claim 1 , wherein more than one silicon core wires are present in the reaction furnace.

4. The method of claim 1 , wherein the source gas comprises trichlorosilane.

5. The method of claim 1 , wherein a surface temperature of said polycrystalline silicon rods during said reacting is in a range of 900° C. to 1200° C.

6. The method of claim 1 , wherein the final diameter of said polycrystalline silicon rods is in a range of 140 mm to 200 mm.

Assignees

• Shinetsu Chemical Co

Inventors

• Netsu Shigeyoshi
• Hoshino Naruhiro
• Okada Tetsuro
• Saito Hiroshi

Classifications

• C01B33/035 Primary

  by decomposition or reduction of gaseous or vaporised silicon compounds in the presence of heated filaments of silicon, carbon or a refractory metal, e.g. tantalum or tungsten, or in the presence of heated silicon rods on which the formed silicon is deposited, a silicon rod being obtained, e.g. Siemens process · CPC title

• B01J2219/0803

  employing electric or magnetic energy · CPC title

• B01J19/087

  employing electric or magnetic energy · CPC title

• C23C16/24

  Deposition of silicon only · CPC title

• C23C16/46

  characterised by the method used for heating the substrate (C23C16/48, C23C16/50 take precedence) · CPC title