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. 19, 1991
Filed:
May. 18, 1990
Minoru Taguchi, Oomiya, JP;
Kazuo Kihara, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A semiconductor device comprising a semiconductor chip formed of a substrate of a first conductivity type and an epitaxial layer of the first conductivity type formed on the substrate, a charge transfer device section formed in the epitaxial layer and driven by a given clock, and a preset region of a second conductivity type formed adjacent to the charge transfer device section in the semiconductor ship. The preset region includes a first layer of the second conductivity type formed in a boundary portion between the substrate and the epitaxial layer, a second layer of the second conductivity type formed on the first layer the epitaxial layer, and a third layer of the second conductivity type formed on the second layer in the epitaxial layer to reach the surface of the substrate. The maximum value of the second conductivity type impurity concentration of the third layer is set smaller than the maximum value of the second conductivity type impurity concentration of the first layer. A bipolar transistor section is formed in the third layer.