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. 09, 1982
Filed:
Jan. 08, 1980
Applicant:
Inventors:
Kazuhiko Yamamoto, Yokohama, JP;
Yoshiaki Matsushita, Tokyo, JP;
Masaru Kanamori, Tokyo, JP;
Kazutoshi Nagasawa, Yokohama, JP;
Naotsugu Yoshihiro, Matsudo, JP;
Seigo Kishino, Hachioji, JP;
Assignee:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ;
U.S. Cl.
CPC ...
148-15 ; 148187 ; 357 91 ;
Abstract
A silicon single crystal wafer is subjected to two-stage heat treatment. In the first-stage it is heated at a temperature within the range of between 500.degree. C. and 1,000.degree. C. Subsequently the thus heated wafer is heated at a temperature higher than that at the first stage. Thus, a nondefective zone is formed in the surface region of the wafer, and the interior zone of the wafer becomes rich in micro defects capable of gettering impurities such as heavy metals.