The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 18, 2013
Filed:
Mar. 16, 2012
Xiangyang MA, Hangzhou, CN;
Ze Xu, Hangzhou, CN;
Biao Wang, Hangzhou, CN;
Deren Yang, Hangzhou, CN;
Zhejiang University, Hangzhou, Zhejiang Province, CN;
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.