Polycrystalline silicon chunks and method for producing them

Patent metadata

Field	Value
Publication number	US-9266741-B2
Application number	US-201313952050-A
Country	US
Kind code	B2
Filing date	Jul 26, 2013
Priority date	Aug 6, 2012
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

The present invention relates to polycrystalline silicon chunks which are cubic and have a metal content of less than 200 pptw and a dopant content of less than 50 ppta. Methods for producing polycrystalline silicon chunks, include the steps of providing a polycrystalline silicon rod, comminuting the polycrystalline silicon rod into cubic chunks, and cleaning the polycrystalline silicon chunks, wherein comminution takes place using a spiked-roll crusher having at least one spiked roll, the spiked roll including W 2 C phases or WC phases with 0.1-10% of a metal carbide selected from the group consisting of titanium carbide, chromium carbide, molybdenum carbide, vanadium carbide, and nickel carbide or consisting of steel with 1-25% W.

First claim

What is claimed is:

1. A method for producing polycrystalline silicon chunks, comprising providing a polycrystalline silicon rod, comminuting the polycrystalline silicon rod into cubic chunks, and cleaning the polycrystalline silicon chunks, wherein comminution takes place using a spiked-roll crusher having at least one spiked roll, the at least one spiked roll comprising W 2 C phases.

2. The method as claimed in claim 1 , wherein the at least one spiked roll further comprises cobalt in an amount from 0.1 wt. % to 20 wt. %.

3. The method as claimed in claim 1 , wherein the cleaning of the polycrystalline silicon chunks comprises the following steps: (a) preliminary cleaning in HF, HCl, and H 2 O 2 ; rinsing with ultrapure water; (b) main cleaning with HF/HNO 3 in an acid circuit separate from the preliminary cleaning; (c) rinsing with ultrapure water; (d) hydrophilization with ozone water; (e) drying with ultrapure air; and (f) cooling with ultrapure air.

Assignees

• Wacker Chemie Ag

Inventors

• Wochner Hanns
• Fabry Laszlo

Classifications

• C01P2006/80

  Compositional purity · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title

• C01B33/02 Primary

  Silicon (forming single crystals or homogeneous polycrystalline material with defined structure C30B) · CPC title

• C22C29/08

  based on tungsten carbide · CPC title

• C01B33/037 Primary

  Purification (by zone-melting C30B13/00) · CPC title