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:
Nov. 07, 2000
Filed:
Jun. 30, 1999
Ken Aihara, Gunma-ken, JP;
Hiroshi Takeno, Gunma-ken, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
There is disclosed a method for heat treatment of a silicon substrate produced by the CZ method by utilizing a rapid thermal annealer, wherein the heat treatment is performed under an atmosphere composed of 100% nitrogen, or 100% oxygen, or a mixed atmosphere of oxygen and nitrogen by heating the silicon substrate to a maximum holding temperature within a range of from 1125.degree. C. to the melting point of silicon, and holding the substrate at that maximum holding temperature for a holding time of 5 seconds or more, and then the substrate is rapidly cooled at a cooling rate of 8.degree. C./second or more from the maximum holding temperature. In the method, the amount of oxygen precipitation nuclei in the substrate can be controlled by changing the maximum holding temperature and the holding time. The present invention provide a method for heat treatment of a silicon substrate produced by the CZ method by utilizing an RTA apparatus, which can provide a silicon substrate having a desired oxygen precipitation characteristic without controlling oxygen concentration in the silicon substrate, and an epitaxial wafer utilizing a substrate heat-treated by the method.