Process of internal gettering for Czochralski silicon wafer

US8466043B2 · kind B2 · utility

Assignee

• ZHEJIANG UNIVERSITY · CN

Inventors

• Xiangyang Ma · Qingdao, CN
• Ze Xu · Cixi City, CN
• Biao Wang · Lo Wu, CN
• Deren Yang · Hangzhou City, CN

Key dates

• Filing date: Mar 16, 2012
• Grant date: Jun 18, 2013
• Expiry date: Mar 16, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/3225
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

An internal gettering process for a Czochralski silicon wafers comprises: (1) heating a Cz silicon wafer to 1200-1250° C. at a heating rate of 50-100° C./s under a nitrogen atmosphere, maintaining for 30-150 seconds, cooling the Cz silicon wafer to 800-1000° C. first at a cooling rate of 5-50° C./s, and then cooling the Cz silicon wafer naturally; (2) annealing the Cz silicon wafer obtained in the step (1) at 800-900° C. under an argon atmosphere for a period of 8-16 hours. The present invention only involves two heat treatment steps which require lower temperature and shorter time comparing to the conventional processes. The density of the bulk microdefects and the width of the denuded zone can be easily controlled by the temperature, duration and cooling rate of rapid thermal processing in the first step.