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:
Feb. 05, 2008
Filed:
May. 22, 2002
Makoto Iida, Gunma, JP;
Masaro Tamatsuka, Gunma, JP;
Makoto Iida, Gunma, JP;
Masaro Tamatsuka, Gunma, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
The present invention provides a method for producing a nitrogen-doped annealed wafer, wherein before a wafer sliced from a silicon single crystal doped with at least nitrogen and polished is subjected to a high temperature heat treatment at 1100° C. to 1350° C. in an atmosphere of argon, hydrogen or a mixed gas thereof, a step of maintaining the wafer at a temperature lower than the treatment temperature of the high temperature heat treatment is conducted to allow growth of oxygen precipitation nuclei having such a size that the nuclei should be annihilated by the high temperature heat treatment to such a size that the nuclei should not be annihilated by the high temperature heat treatment, and then the high temperature heat treatment is performed. Thus, there are provided a nitrogen-doped annealed wafer with reducing variation of the BMD density after the annealing among silicon single crystal wafers sliced from various positions of the silicon single crystal without being affected by concentration of nitrogen doped in a silicon single crystal and a method for producing the same.