Method and device for producing high purity polycrystalline silicon with a reduced dopant content

US7927571B2 · kind B2 · utility

Assignee

• Wacker Chemie AG · DE

Inventors

• Thomas Altmann · Burghausen, DE
• Hans Peter Sendlinger · Altötting, DE
• Ivo Croessmann · Hamburg, DE

Key dates

• Filing date: Aug 6, 2007
• Grant date: Apr 19, 2011
• Expiry date: Jul 6, 2029

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B33/035
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

In the batch production of high purity polycrystalline silicon, in which a U-shaped silicon carrier body is fastened in an open deposition reactor, the deposition reactor is hermetically sealed, the U-shaped carrier body is heated electrical current, a silicon-containing reaction gas and hydrogen are introduced into the reactor through a supply line so that silicon from the reaction gas is deposited on the carrier body, the diameter of the carrier body increases and a waste gas formed is removed from the deposition reactor through a discharge line, and, after a desired diameter of the polysilicon rod is reached, deposition is terminated, the carrier body is cooled to room temperature, the reactor is opened, the carrier body is removed from the reactor and a second U-shaped silicon carrier body made of silicon is fastened in the deposition reactor, an inert gas is fed through the supply and discharge lines into the open reactor from at least the time when the reactor is opened to extract the first carrier body with deposited silicon, until at least the time when the reactor is closed in order to deposit silicon on the second carrier body.