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:
Mar. 30, 1993
Filed:
Sep. 28, 1990
Hideo Matsuda, Yokohama, JP;
Susumu Iesaka, Tokyo, JP;
Takashi Fujiwara, Yokohama, JP;
Michiaki Hiyoshi, Yokohama, JP;
Hisashi Suzuki, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A crimp-type semiconductor device is provided with a semiconductor substrate having a lifetime-controlled region. This lifetime-controlled region is in the form of a ring, and the lifetime of the minority carriers is shortened in the region. Second-conductivity type impurity regions, which serve as emitter layers, are formed on the semiconductor substrate such that they provide a plurality of concentric arrays. The inner diameter of the ring-like lifetime-controlled region is longer than the diameter of an enveloping circle which is obtained by connecting the radially-inner ends of the impurity regions of the outermost array.