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:
Jul. 23, 1991
Filed:
Dec. 19, 1989
Youji Yamashita, Yokohama, JP;
Masakatu Kojima, Yokosuka, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A crystal pulling apparatus of double structure crucible has a crucible body which is divided into inner and outer chambers by a cylindrical partition wall coaxially disposed in the crucible body. A melt supplying path used to supply melt from the outer chamber of the crucible to the inner chamber in which the crystal is pulled is formed of a small through hole formed in the partition wall or the small through hole and a pipe-like passage formed in communication with small through hole. The radius of the inner chamber of the double structure crucible has a specified relation determined by the segregation coefficient of dopant impurity with respect to the radius of the outer chamber. This is, the radius of the inner chamber is set substantially equal to .sqroot.k times the radius of the outer chamber when the segregation coefficient of the dopant impurity is k. In the crystal pulling apparatus with the double structure crucible, a small chamber for introducing dopant is disposed in the outer chamber of the crucible to be in communication with the inner chamber.