Systems and methods for production of low oxygen content silicon

US11136691B2 · kind B2 · utility

Assignee

• Globalwafers Co., Ltd. · TW

Inventors

• Gaurab Samanta · Chesterfield, US
• Parthiv Daggolu · Creve Coeur, US
• Sumeet S. Bhagavat · Holden, US
• Soubir Basak · Chandler, US
• Nan Zhang · San Diego, US

Key dates

• Filing date: Jun 30, 2020
• Grant date: Oct 5, 2021
• Expiry date: Jun 30, 2040

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C30B30/04
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A method for producing a silicon ingot includes withdrawing a seed crystal from a melt that includes melted silicon in a crucible that is enclosed in a vacuum chamber containing a cusped magnetic field. At least one process parameter is regulated in at least two stages, including a first stage corresponding to formation of the silicon ingot up to an intermediate ingot length, and a second stage corresponding to formation of the silicon ingot from the intermediate ingot length to the total ingot length. During the second stage process parameter regulation may include reducing a crystal rotation rate, reducing a crucible rotation rate, and/or increasing a magnetic field strength relative to the first stage.