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:
Apr. 07, 1992
Filed:
Apr. 29, 1991
Kazuo Miwada, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A charge transfer device is fabricated on a semiconductor substrate of a first conductivity type and comprises a well formed in a surface portion of the semiconductor substrate and having a second conductivity type opposite to the first conductivity type, a charge transfer region of the first conductivity type formed in a surface portion of the well, a floating diffusion region of the first conductivity type formed in the surface portion of the well and contiguous to the charge transfer region, an insulating film covering the surface portion of the well, and a plurality of gate electrodes provided on the insulating film and applied with driving clocks in such a manner as to produce conductive channels in the charge transfer region for transferring electric charges toward the floating diffusion region, in which the channels in the vicinity of the floating diffusion region are gradually decreased in width toward the floating diffusion region, and in which impurity atoms of the well beneath the charge transfer region in the vicinity of the floating diffusion region are graded toward the floating diffusion region, so that the electric charges are allowed to be swept thereinto without any residual.